Sunday, January 07, 2007

Quiet Generator Muffler

For the very first Nerdy Thing I Do (NTID), I'll introduce you to the quiet(er) muffler I fabbed up for my portable generator.



I purchased the generator from my local Home Depot for use with my 5th wheel trailer. The soon-to-be-wife and I go camping a fair amount around Moab, UT, and it gets hot hot hot there in the spring and early fall. So having the A/C available while in the middle of the desert is a nice thing. To be honest, the generator was an impulse buy. I was looking for something else at HD (no doubt an odd sized drill bit that I just HAD to have for a project) and came across it at the end of the isle. It was marked down considerably since it was returned and "reconditioned." I don't remember what the price was, something around $300, but it was darn cheap for a 5kw generator (burstable to 6250w)! I knew the silly thing would most likely be louder than I really wished, but I figured, "WTH, might as well." (I would really really really like one of those fancy Honda super-quiet EU jobbies. That would rock. But I just can't swing the $2000 bucks for the appropriate sized unit.) So I came home with the Coleman/Briggs & Stratton option.

One trip to the desert and I wondered if I had made a mistake! The noise inside the trailer wasn't horrible...the roar of the A/C did a nice job of filtering out the racket of the generator...but the noise outside was considerable. I felt sorry for my buddies that were camping with me. (Although they all had there own generators running as well.)

So began my quest to try make this generator quieter. Lots of Google searches later and I came up with very little. I did find one option that I was tempted by. SuperTrapp makes a version of their tunable muffler for small engines. And people claimed that it worked really well! (I have a SuperTrapp on my Honda XR650R and really like it. It's loud...but only because I have it tuned that way. They can be quiet.) I found the info here. The info was encouraging, but the price was not. Over $100 for a muffler on a cheap-o generator just didn't make sense. I scrapped that idea.

I can't remember where I came up with this idea. It may have been while I was searching CraigsList for tools (which I do often). Someone was selling a generator and mentioned that they had become tired of the noise and stuck an old motorcycle muffler on it. Ka-Bing!! That should work, I figured.

So then my brain kicked in and I started pondering what motorcycle muffler would work. I finally settled on a sportbike muffler. My reasons were 1) from the factory, most crotch rockets are pretty darn quiet, 2) they are certainly rated at a high enough CFM so constricting the exhaust won't be an issue (calculate 600cc X a Gazillion rpm), and 3) any self-respected sportbike rider takes their cycle straight to the aftermarket shop from the dealer and has that shop install a free-flowing pipe for the added 5.9hp...which means there's got to be loads of this aluminum babies to unload! The market is literally flooded with stock take-offs from crotch rockets! Search ebay and see for yourself. Being an upstanding member of the "Ride Red" club, I, of course, could only consider Honda products. After a 2 minute search on ebay I came up with a take-off from a 90-something CBR 600 F3. For a cool $13.50! Of course no-one else wanted it, so in a week's time I had it in my Nerdy little paws.

Here it is, straight out of the box.



Here's a pic looking down of the stock muffler on my generator (with top fuel tank removed). Sort of boxy affair at best.


After some chin-scratching consideration I decided to mount the muffler in a vertical way. Make sort of a big-rig stack look for it. I originally thought I could fab up some sort of adapter that would attach directly to the outflow of the OEM muffler. Bad idea. 1) there's was no way to solidly attach a fairly hefty aluminum unit, and 2) I couldn't figure a good way to make a tight seal. I didn't want any hot exhaust gases (and sound) spraying out radially around the connection. So I decided on a whole new exhaust manifold/pipe arrangement.



I fabbed up a new flange to bolt directly to the engine head out of some 1/4" scrap I had laying around. I did buy a new gasket from the local small engine shop.





Since the space was somewhat limited I decided to make the exhaust piping out of 1" threaded black iron pipe. Cheap stuff and easy to come by. I did have to make one custom cut/weld near the flange to achieve a custom angle. The rest I fabbed from standard fittings.



I decided to use a standard pipe flange (for mounting pipes to flat surfaces) as the interface between the pipe and muffler. The diameters matched up pretty well and there was a good flat surface on each to make a good seal with. I tried to find some high-temp exhaust gasket material but failed. I ended up making the gasket/seal with some plain old fiberglass muffler packing. I just created a loose donut of material then clamp it flat and tight between the muffler and the flange. No leaks.





After one trip to the desert I'm quite pleased with this setup! It's MUCH quieter and I like the fact that the exhaust exits up (I run the generator in the bed of my pickup) instead of to the side. It effectively lowers the operating temperature of the unit (since the the old muffler cavity is just air now) and the majority of the sound is projected upwards instead of out. In doing a little research for this project I found that most people did say "You'll be surprised how much actual engine noise there is once the exhaust is toned down." It's true! These little engines aren't designed to be quiet. I don't know what's actually producing the noise, but there's a considerable amount. I guess it's the combo of bearings, valves, crankshaft, rod, lifters, and piston all added together that makes the noise. At any rate...I would highly recommend anyone make this mod to there small generator to help quiet it a bit. For around $50 it's well worth it!




115 comments:

Anonymous said...

I am having the same issue with my generator and was going to try and find a Yugo muffler or something, but the bike pipe was an awesome idea!! I have the same setup generator as you do and was wondering if you could help with where you got the new flange for attaching to the actual generator. i was thinging of using my original but if anything goes wrong I will have to find one anyway. Also, from the pipe to the exhaust you mention fiberglass packing, but do you think there are fittings out there for that? I know this was posted a year ago, but maybe I'll get lucky and you have an email alert setup or something.

Thanks for your pictures and description!!

-Dan

Joel Jennings said...

Dan,

Oh, I'm still here. Just contemplating my once-a-year posting! Haha. Anyway. I fabbed the flange myself. It took maybe an hour to do. A good bi-metal holesaw will help out for the middle. I think I used 1/4" steel. Then I just work with a hacksaw, diegrinder, and file for a while. As for the fiberglass, I tried to get some exhaust gasket material, but no one in my town had any and I just HAD to finish up. It works just fine. Glad this helps! That's the point.

Joel

Anonymous said...

Well I made my trip to the local Home Depot thinking you found the flange there until my brother called me and read me your statement! I will go ahead and fabricate the flange and try to take some pictures to add to your blog. I was thinging of incorporting an aluminum box filled with baffling to the end of the muffler to aid in noise reduction! I'll let you know how that turns out. Thanks for the input and please check back due to my awaiting questions.

-Dan

Anonymous said...

Thanks for all the comments guys, I got a lot of ideas from your posts. I bought a 5500 watt gennie from Costco. It was unbelieveably loud. I wanted to put a motorcycle muffler on it, yet retain the stock muffler just in case. So, I welded a 90 onto the opening of the stock muffler. Bought some of that flex muffler pipe from my local autoparts store. Hooked the flex pipe to the 90 and ran it under the motor to the other side where I hooked it to a Hayabusa muffler that I hung on the side with rubber muffler hangers. I haven't had a chance to run it yet, but the system looks and should work cool. Not only do I get the benefit of the stock muffler, but also the added quiet power of the cycle muffler. If space becomes a problem, I can unhook the cycle muffler and still use the stock muffler.

Joel, it seemed to me the weakness in your design was the fact the muffler has to move with the generator and your set up looked very heavy with the only support coming from the two head bolts. If it worked, then cool. My set up was quite heavy so hanging it from the rubber hangers allowed it to move freely with the vibration of the motor, yet the hangers carried all the weight. Hopefully it works the way it should when I fire it up. Thanks again for the rgeat post.

Steve

Joel Jennings said...

Steve,

Glad you've got one set up.

I didn't detail it I guess (I thought I did) but I did build a quite involved bracket system that holds the muffler and pipe tight to the engine. The whole assemble moves with the engine. So rest assured that the whole weight of it doesn't rest on the head! That would just be crazy.

Sounds like your system would work well, too. Maybe better.

Thanks for the comments!

Joel

Anonymous said...

I finally got it fired up and man oh man is the motor loud. The sound coming out of the muffler is very quiet, but the motor itself shakes the house. I'm thinking about putting some type of louvered sides on it that still allow circulation but block some of the noise. I've heard of people laying plywood or drywall up against the sides, but I was thinking something more permanent that I could actually mount to it. Any ideas?

Steve

Brian LaFluer said...

Joel,

I just got my first RV and
I have the Coleman Powermate 6250 Watt Generator.
As you said it is LOUD!!

I 'm going to take your great idea and build the sport bike muffler for mine.
I just wanted to ask how much noise did it cut down on?
Like %50 or more?

Joel Jennings said...

Brian,

I can't really quantify how much sound it cuts out. It's significant though! There is a lot of engine noise. Having the muffler point up I think helps the quieting as well. In the end...eh...maybe %50.

beek said...

I used a Walker 18136, (available at O Reilly) it is an oval muffler that has 1 1/2 in and 1 1/4 out, it got the noise down to where I can now hear the lifters and the recoil starter rattle, I guess I'll have to live with that. A welder is a 'must have' for this project it was not a bolt and go. The muffler size looks like it was made for this generator. (Coleman Powermate, square tube frame) Pics available

Malc said...

Awesome!

Anyone of you hear knows if Vance and Hines Exhaust can be use to generator too?

Joel Jennings said...

Don't know why it wouldn't work. Probably be louder than the OEM unit I used though.

Chris said...

My wife and I just had a well dug on powerless property in Ala.. I bought a DeVilbiss PowerBack 5250 gen.from a co-worker for $375, 10 years old, never used, runs like brand new. Guess what? NOISEY!!!!!
I like the bike muffler idea. I work with a lot of dirt bikers and might find one easily. Also, I designed and built an insulated pump-house (double insulated, sealed tight and looks like a log cabin)for our well that I can duplicate and alter to house the gen..
Thanks for the info and I will let you know (along with others) how your idea is progressing!!

Chris

Joel Jennings said...

Chris,

Surrounds work really well for generators that don't need to move much. I like your tiny-cabin-in-the-woods idea. Nice. Dirt mike muffler will work. Although I think you might find that a street bike muffler will end up being quieter. There's just more meat there to absorb the sound. Thanks for reading!

Anonymous said...

hmmm, i was just wondering... Ive heard bikes run and they seem quite noisy, but on the other hand my car runs and i don't even know its on.
so im wondering if it would be possible to use a car muffler/straight pipe, to have a quieter effect??

Joel Jennings said...

Dear Anonymous,

You could absolutely use a car muffler. I chose a motorcycle muffler because 1) it looked kinda cool, 2) it's aluminum, 3) it actually works really well. This is an OEM/Stock muffler from a Honda 600 sport bike. It's not a Harley "muffler". It actually does a really good job. As I've said numerous times, the engine noise is louder than the exhaust noise now. But, do whatever you like! The right car muffler would work great for quieting your generator down.

beek said...

I used a Walker 18136, (available at O Reilly) it is an oval muffler that has 1 1/2 in and 1 1/4 out,that is a small car muffler to use the complete system may get kinda long but I guess that would help to quieten it, also the catalytic converter helps to reduce noise on a car

QuickRick said...

Joel,

Thanks for your efforts. After listening to our Tecumseh powered Coleman gen set similar to yours for 3 days, I did your mod. I used an old Haybusa muffler off a friend's bike plus your plumbing system.(on a Tecumseh 11 hp OHV it exhausts out the other side) I used a large washer drilled and welded as my "two bolt flange" but it looks the same. The muffler is suspended by a rubber hanger spring mounted for movement.
The results? 103 db of sound at the muffler of the original generator stock/ now 92 db noise at the muffler area of the modified generator currently. The threshold of pain has been greatly reduced........ I'm no scientist but I think this is vast.

Joel Jennings said...

Hey QuickRick,

Well put..."I'm not scientist, but I think this is vast." I'm pumped that more people are finding this post. That was my intention. When I looked for info on this subject, I came up with zilch.

Joel

Lynn said...

Is the bike muffler you used a straight thru design or is it baffled inside? I have found something to use but wanted to check with you before I buy it.

Joel Jennings said...

Lynn,
I honestly can't remember for sure which type of muffler it was. Since I have to guess, I'd bet it's a straight-through design since it came from performance cycle. It may have had had an interior "cone" or some such that would act as a baffle would. But I'm still going with straight-through. I came from a Honda CBR600 after all.

Anonymous said...

Some good ideas, some not so good. The motorcycle muffler idea is not likely going to reduce the noise level by much due to the fact that they are designed to be louder than the stock muffler, with engine performance being the desired results. The only idea that I can contribute, is maybe using the "screw together" flange connection that is used for natural gas (furnace) connection. This would allow for the muffler to be removed if there is a space concern during transport.

Joel Jennings said...

Think whay you may... The end result is a DRAMATIC reduction of exhaust noise.

QuickRick said...

Earlier I had said that I measured, with a decibel meter, the "before and after" sounds of this modification. Unless you have an example or are a pysicist, a reduction in sound from 103 to 92 decibels is fairly meaningless. If you click on this link and activate the second "1 decibel" chart, you will understand what a huge difference 11 decibel reduction is. Try calling the first noise 1 and the second noise 2 as you count down to number 11. Scientifically it is in the neighborhood of over 50-60%.
A sportbike muffler is quiet, because it is made to satisfy state noise standards so it seems to work in this instance very well. (I still don't want this machine operating in my living room)

http://www.co-bw.com/Audio_what_is_decible.htm

QuickRick

Anonymous said...

This is great! Just what I was looking for and I can't wait to try it out. You're right that there isn't really anything else detailing this out there right now.

Glad to have stumbled upon your site. Thanks!

Jon

Joel Jennings said...

Thanks Jon. I hope this helps you in your quest for a quieter campsite!

Joel

Anonymous said...

All of the muffler ideas work well. I have seen many different configurations over the years to quiet cheap noisy Gen Sets. Adding a good muffler will decrease the noise level signifacantly..and then by pointing the exhaust up helps as well. One thing you should all address is the fact that by pointing the ehaust up you can allow water to enter. Ensure you keep a can or use another method to keep water out. This will ruin your Generator. If the generator is not to be moved, you might think about running the exhaust even higher to the point the muffler is above your head. But of course this will require stablilazation..In a building like the gentleman in Alaska has is a prime example of this. I personally used my well house, added vents near the bottom, and ran the exhaust out side near the top, Inuslated the building, and now,,If you are 25 feet from the building you can barely hear the Generator running. Cheap gen..briggs engine. I also added a conversion kit to the carb and now can run it off propane, natural gas, or gasoline. Kit was about 150 bucks used on ebay..nice addition as folks are alway fighting for gas in Texas when it is Hurricane time..

Joel Jennings said...

All good suggestions! My generator lives 99.5% in the garage. The other .5% is in the bed of my truck when we go camping. I have a motocross style muffler plug that I stick in the end during transport and non-use. Only problem is I invariable forget to take it out before I pull the start cord. It usually comes out with champagne POP, sails about 40 feet in the air and then lands on my head! You'd think I'd remember after this happens 37 times.

Cheers,
Joel

Anonymous said...

Just got the Coleman from a friend. Need to stealth it out for my own sanity. What is the max decible reduction we can attain? I want this thing to per like one of those little brief case size generators, is it possible?

QuickRick said...

Anon,

I doubt that you will ever get a Coleman as quiet as a small suitcase sized unit....it is diminutive in size and HP. Even if the exhaust made no noise at all you'd still have the motor drivetrain din as well as the recoil rattling etcetera. Our mods just make it "much improved" is all.

QR

Joel Jennings said...

Quickrick is right. It will never match the little Honda EU generators. There's just too much going on in the B&S engine for that to happen.

QuickRick said...

ANON,

You will never make these larger generators as quiet as the diminutive suitcase model. Even if the exhaust made zero noise, you'd still have that engine valvetrain, starter recoil rattle etcetera making noises that can't be masked.The next step is to surround it with noise abatement material (remember though" it is an air cooled motor)

QR

Pennywise said...

Keep in mind a fully synthetic oil will help quiet the engine noise. Royal Purple works great if you can afford it. In addition to a new larger muffler grab one with a lot of baffling and the largest your can fit) pointing up, if you build an enclosure for the generator with sound deadening insulation, and suspend it in the box with rubber mounts..while it won't be pretty it will certainly be quiet. Throw some wheels on that enclosure and you're set. Some of these champion equipment generators are getting real popular because of their quality and price, but are still 70-80 dba. At $250, I don't mind spending the extra 100 to fab my own box and muffler. That's quality and quietness for CHEAP. I do motorcycle racing on the side, quiet generators are GOLD.

Anonymous said...

Don't forget you need airflow. The sound insulated box needs to be cool. So wherever you're running the generator, make sure the temperatures aren't hot. If it is, well, you just might want to throw a fan on it too.

Anonymous said...

Hey guys thanks for all the info. I have a generac 5500 that is killing the neighbors when we have a blackout. I used one of there kits and the stand up muffler design with 1" flexible SS exhaust off the old maifold pipe. I havent' fired it up yet but am expecting good results. You would think the generator idiots would have built one of these already and made it stock. Thanks again!!!!

Christian

Sir Pizza said...

Fantastic! Thanks for the post! I unfortunately don't have the time or tools to fab anything up (wish I did 'cause it's fun) but I'm thinking any muffler shop can cobble together a flange and exhaust pipe leading into a Honda car muffler. Then with some 2X4 and 3/4 inch plywood and casters I should be able to box it in so the engine noise will also quiet down a bit. Bring on the hurricanes! Wait...don't.

Anonymous said...

First I want to say thanks for opening this post for discussion for i have been hearing noise for some time now. Right before Hurricane Ike Hit us I purchased a generator from o'Rielly's a Champion...and let me tell you after 10 days of hearing the noise from this generator I was ready to go nuts.I seen one post about a guy that used metal flex hose and a THRUSH car muffler Seemed to work quite well and you could mount it any way you wanted or lay it on the ground . Undo the muffler clamp and it could be stored ...but I do like the motorcylce muffler also.One more thing i seen was someone had it boxed in on three sides and had box fan plugged in blowing cool air in the box ...blocked the noise and cooled the motor also...another good idea.

Anonymous said...

One reason the crotch rocket factory mufflers work is because all sound has a frequency and the faster the engine runs the frequency cycles get closer togeather and the muffler appears like a straight pile to the engine.At lower rpm the cycles pass through the larger section of the muffler where the baffels and packing are located.Also you can reduce valve rocker noise by getting some of the black tar like insulation used on car air conditioner lines where they are located under the hood.Cars had a lot of noise in that rocker area untill they started making thicker cast aluminum valve covers.Then came hydrolic lifters with 0 lash.Hope that sparks some more ideas--like putting a flapper on top of the muffler like diesle trucks have to keep rain out.

Anonymous said...

I remember a post I read years ago about a person who burried a 55 gal drum with holes in the bottom and piped in the exhaust from a generator. He said the only noise left was lifter and engine drive train noise. I had always been curious if this would really work for a stationary generator. Any other thoughts?

offgridbob said...

I'm building a cabin right now and plan on burying a big electrical box in the side hill with only the front exposed where the door is, then if I run the muffler vertical like you said in an earlier post, and surround it with dirt.I will surround a vertical vent with the dirt also then I will put a fan on the front door and run it off the generator to keep the air surcculating

Anonymous said...

Thanks for the ideas . I recently got a gen set on the cheap and have been wondering how bad could it be . After sending the kids running out of the garage covering their ears I decided I better find a muffler for this old monster . That cast iron 11.5 hp Briggs came to life with a roar and no muffler what so ever . The original owner had screwed a piece of 1.5" x 2' pipe into the head and that's it .The only consideration was for the valves and the head itself so as not to suck cold air back in and warp everything . Every stroke at high rpm sounded like a 12 gauge going off. Needless to say , one quick search and I found your post \ plan . And me , my family , and every family 5 houses either side , will appreciate the upgrade !!

Chuck said...

Great ideas, I’ve had a 5000W genie for years that gets run at least once a year during power outages. I would like to mod myself, but I have no real mechanical aptitude, or welding equipment. Should I go to a car mechanic, muffler shop? What would be easiest to come by and rig up, a car or motorcycle muffler? Is backflow a concern?

Joel Jennings said...

Chuck,

I'd think a muffler shop could fab you up something that would work. I don't think backflow, or back pressure, is any concern since these engines just don't push that much air. Any car or motorcycle muffler would work in my opinion.

Joel

Anonymous said...

All Great posts! Maybe by now someone should make a over the counter Mod kit. I have both GEN the honda EU is amazing but too expensive and not powerful enough. The other sid is the B&S Storm 5500W. Great power buit high vol. If any manufacturers are out there the time is right for a MOD kit!
Can the new quieter muffler be ported out of a quiet box? Maybe an old metal shed with fiberglass insulation & metal retaining studs?


Keep up the Great thinking..

jmanch said...

just bought a generac gp5500. they claim it has a "low tone muffler". maybe i have mistook the definition of low, but it is quite LOUD. from what i gathered a sport bike muffler, or a Walker 18136 muffler. which would be more suitable, and could i install that in conjunction with the stock p.o.s muffler
thanks j-

Fritz Von said...

I have Coleman 5000 with a 10hp Tecumseh HM100. The exhaust outlet is tapped for 3/4 NPT, so it was as easy as screwing a pipe in there and bolting the muffler to it.

It was till pretty loud, so I dug a hole and buried it.

Anonymous said...

I just installed a Walker 18479 muffler from pep boys on a 2250 watt 5 hp Coleman Generator. I used a 3/4 pipe nipple and 1 90 deg elbow out of the engine and pointed up. Another 3/4 nipple and a 3/4 by 1.5 reducer were added. I bored out the 1.5 end on a lathe to take a slip fit of the o.d.of the muffler pipe. This connection was brazed together. The muffler was installed vertically and a brace was added between the muffler and generator frame. The engine is quieter and not as harsh sounding but nowhere near as quiet as a Honda. I'm going to add exhaust wrap to the piping. I think that will muffle the "bell" effect of the piping.Extending the "tailpipe" also smoothes out the exhaust pulses.

Bill D said...

Hi Joel, Great idea I am starting a similar project on my 11 hp DYNA 6000.Mine has a decal that reads "Quiet Power "and they say engineers don't have a sense of humor! when I used it during a recent power outage neighbors from 4 houses away complained so much I just shut it down and threw out all the frozen stuff next day! So here I go I have bought all the plumbing stuff $60 and a walker muffler #18136 $33.00 I am also adding 10 inch wheels no doubt the same engineer thought that dragging 300 lbs of steel across the garage floor sounding like fingernails on a chalk board was something most people would love! I will let know how I make out in a day or so. Great article by the way not to much else out there.

mrz333 said...

How to quiet a noisy genset seems to be a never ending search. I'm glad I found your site and the great ideas and comments within.

Greyrooster said...

I looked at all the obtions to quiten my coleman 6250 generator. I came up with the best solution for me.
I gave the coleman to my son in law and talked the wife into buying me a honda 3000 ei electric start.
I guess that makes me a lazy bum but I'm happy. Enjoyed this postings very much.

Anonymous said...

DO you think leaving the existing muffler and adding a motorcycle muffle by way of flex tubing will help on a 7hp engine?

Anonymous said...

Here's another idea. Look for a generator with a 4-pole Alternator. They run at 1800 rpm, slightly above an idle. Require twice the HP as the std units you all have, but it is very quiet. Mine is an old 4800 watt Homelite with a 16hp Kohler cast iron engine.

Bill D said...

Hi Joel I took your idea and modified it to fit my generator if you care to see it go to quietergenerator.blogspot.com

I would like your opinion since it was your idea that inspired me I have wanted to do something about the noise for years but needed a push to get it done It worked great Thanks for the great idea

Bill D said...

Sorry Joel I mistyped the blog address

It should have been "aquietergenerator.blogspot.com"

sorry for the newby mistake

ChescoPride said...

Hello all, I plan on doing this real soon. I have a Coleman MAXA 5000 Plus er and it is LOUD! Thankfully my exhaust port is threaded so this should be a little easier then fabricating a connection.

Hi Bill D, I checked out your link, very cool. I think i am going to wrap my exhaust piping with some tape also. Good idea.

I'll let you all know how it turns out. This post is 3 years old and still running, did you think that would happen Dan??? :-)

QuickRick said...

purbodiChesco,

The reason that this 3 year old posting has "grown a life" is because generators used to be noisy, still are today and will be tomorrow.
I had to use ours recently after a storm and the muffler mod helps lots. It is like the difference between.....your wife yammering at you vs. a friend having a normal conversation with you.

QuickRick

Anonymous said...

Thank you Joel for the info. I am doing a research on modifying my honda generator to a Geet engine. To make it run on 0.3 liters of gasoline per hour vice the common 1.2 liters/hr. Your mods would help quieting the engine. Muchos gracias, mahalo, salamat po. AJ

Anonymous said...

Are you guys that modify the muffler worried about back pressure(other) damaging your generator engine?

Joel Jennings said...

Anonymous,

I mod I did here has far far less back pressure then the stock muffler. So, no, I'm not worried.

Joel

Bill D said...

The 4 cyl car motor that this muffler was made for created a lot more exhaust gas than my little 11 hp Briggs does some back pressure isn't a problem

Anonymous said...

Even a brand new 2011 Coleman(?) 5.5kw genny with a huge muffler is freakin' loud! The stock muffler is gigantic by small engine standards; maybe 6" tall, 10" long, and 3" thick (just the actual muffler body not including exhaust tubing and tailpipe). Exhaust can be loud if the muffler is old and worn out but I think the best bet is probably a new stock-type muffler, distance, and a barrier between you and the generator. A 4x8 sheet of plywood or OSB propped on edge near the generator would greatly reduce the sound transmitted in one direction. To keep from worrying about heat/fire issues I would limit myself to plywood no less than 3 feet from the generator on two sides. I bet an old mattress between you and the generator would also be quite effective.

Cliff said...

Having read about the success everybody else had with alternative mufflers, I managed to get 3 on loan from the guy who services my ute but was devastated when not one of them made any appreciable difference to my shiny new AEG 5000W single cylinder 4 stroke air cooled diesel generator. It seems the only way to get some peace is put in my neighbours yard, bury it, or build a wooden enclosure with some sound deadening padding inside. My main concern with putting it inside an enclosure is keeping it cool. Summers in Christchurch, New Zealand can be quite warm!

Joel Jennings said...

Cliff,

I think think the diesel nature of your generator makes it whole different animal. Not sure what to suggest. Though there are people that have built wood enclosures successfully and still kept there machines cool. You do need to think about the airflow in and out and where it goes and comes from and supply sufficient vents in those locations.

Joel

mattHHW said...

Good article - I just bought a Briggs and Stratton 800 watt model 030471 and it is LOUD. I'm planning on building a small shed around it with a couple air vents and an exhaust fan that can double as a doghouse when I don't need the generator.

Anonymous said...

I have a Coleman Powermate 5000 Watt/6250 Peak Watts, with Tecumseh HM-100 10 HP. I talked to a repair person before adding a car muffler to mine. He said that there are female pipe threads where the stock muffler mounts, and you can thread standard pipe in there. But be sure to use a flexable setup. If you do not have flex in the pipes the something is going to give with all the vibrations from the engine. I used a flex pipe from McMaster-Carr that is SS and has the pipe threads. I found a muffler at Advance Auto that has a heat shield. I welded flat steel to the heat shield, and that bolts to the bolts on the electric section. I also installed an extra heat shild plate to keep heat away from the electric section. You still require ear protection to be around this unit, but when you are in a house the noise level is much lower.

You can find more about this by doing a googe of bobistheoilguy JimPghPa Coleman

Anonymous said...

Rediculous

Anonymous said...

I just attached a 2000lb ATV winch on my generator (Honda 10,000PPM Northstar) to get it in and out of my truck bed with ease. Now i am going to follow your idea, it is great! i ordered a flow master silencer muffler that are made to attach to the pre-existing muffler of a ATV to silence it for hunters to use. It was $100 (shipping included), cant wait to see how it bolts on and works. Thank you for your post, it helped me a lot.

pdxr13 said...

I will second the suggestion of finding a 1800 rpm genset, like Onan/Kohler, likely pulled from a scrap RV.

I have an Onan BGE (4.0KW) from 1985 and except for the exhaust, it's pretty quiet. It's heavy at over 200 pounds. It has flathead (L-head) design and is an aircooled 750cc twin with mechanical points and no distributor (wasted spark). Reliability is legendary, probably due to 5 quart oil pan and small-car-size oil filter. The factory service manual and most parts are available.

Since it's not in an RV compartment any more, I'm not limited to muffler size or exhaust routing. The idea of cheap take-off factory stock motorcycle exhausts is a good one. There are some motorcycle shops around that I will inquire at.

Cheers.

SCG said...

Just to pickup on what someone had mentioned back a few posts ago, a longer exhaust pipe also has amazing results. My old MH had a 6.5 KW Onan installed by the PO. It was mounted under the BR in a storage compartment, w/the exhaust running down and straight out the back of the MH, about 1" OD, w/NO MUFFLER. It was about 6ft long overall, and you could be in bed w/it running, and have no problem sleeping. It was not Honda quiet, but close to it. FWIW

SCG said...

Just to pickup on what someone had mentioned back a few posts ago, a longer exhaust pipe also has amazing results. My old MH had a 6.5 KW Onan installed by the PO. It was mounted under the BR in a storage compartment, w/the exhaust running down and straight out the back of the MH, about 1" OD, w/NO MUFFLER. It was about 6ft long overall, and you could be in bed w/it running, and have no problem sleeping. It was not Honda quiet, but close to it. FWIW

Unknown said...

Well I have to say this thread has some great information in it. If I may continue adding to it (in the form of questions), I had a few questions about building an enclosure. I got a Champion 7000/9000 portable generator from Costco. Thing is loud. I was toying with the idea of leaving it in the garage and sending the exhaust out via a duct but I realize that's simply not safe for many reasons.

So first question is what's the best way to extend/redirect the exhaust. I see there's a metal plate with three screws that holds the screen spark arrestor in place. Do I just take that off and find something that will "attach" to the exhaust using the same three screws? I was going to use flexible duct to redirect the exhaust of of the enclosure and maybe direct it down into a hole or up.

Another question is my generator dimensions are roughly 28x27x27. I would like enough room to move around in the enclosure so I was thinking of something like this:

http://www.rubbermaid.com/Category/Pages/ProductDetail.aspx?CatName=Outdoor&SubcatId=HorizontalSheds&Prod_ID=RP091380

There are smaller ones it will fit in, but I thought giving some room would be good. Is it better if I'm going to install fans and whatnot to have a smaller space for the generator or as long as the air is moving it should be okay even in a larger space?

I do plan on adding insulation and soundproofing material to the enclosure or at least the foam board with reflective surfaces to keep the plastic from getting hot.

QuickRick said...

Unknown,

Yes you could remove the muffler and do as Joel did to create a take off exhaust flange by fashioning a flange of material and drilling it. I took the easier route and used a large washer that had an opening as lasge as the removed muffler opening. I used the muffler to mark my holes for accuracy and welded a length of 3/4 inch tubing to it as a take off. Once you have this attached you can go anywhere you want....or like Joel and me, into a motorcycle muffler.

QuickRick

homerrulesall said...

Thanx QuickRick (and you are quick). Problem is I really don't want to mess with it too much so all I planned on doing is removing just the spark arrestor screen which is held on by a circular collar with three bolts and then replacing the assembly with a duct or tubing to redirect the hot exhaust out of the enclosure leaving the muffler in place. Is the problem with that that I'm really not solving the heat issue? I planned on wrapping the pipe or using insulated flexible duct.

Joe

QuickRick said...

Homerulesall,

Well you know, that could work so long as it doesn't leak. You could also screw the duct right to the muffler itself as an option. The flex duct may be kind of thin I am thinking so I hope that noise doesn't find its way through your duct. You are right to then wrap it, the pipe that leaves the Tecumseh I have gets so hot that you could toast your skin on it.

Who knows, you may be onto something as long as you route it far away from the machine.

There is also 3 inch round smoke pipe used to vent gas water heaters that would be thicker yet still field adjusted.....thought of using that? It is much more ridgid and could be insulated easier.

QR

homerrulesall said...

I'm not sure why I would care if it leaks a little. The entire setup will be in a garden enclosure (I think a Suncast GS3000). Seems roomy enough, I just want most of the exhaust out so I can reduce the heat inside the enclosure, and also possibly muffle or redirect it once outside if need be. I still plan on having one or two exhaust fans in there and input ducts on the other side to keep air flowing over the setup and reduce engine heat. The whole setup will be outside. I agree I might go for a sturdier setup to exhaust the output of the muffler, but the way these are made makes it tough. I liked the idea of insulated flexible duct as I would think it wouldn't require decent bracing (I hope).

In a way I'm mimicking this setup though he doesn't have enough airflow I believe...
http://www.youtube.com/watch?v=62-mNynTa0M

IGnatius T Foobar said...

Nice info here. Would this method work with a diesel generator? I've got one of those typical chinese 186F type engines with the combined muffler and catalytic converter. I see nothing in this thread about the effects of removing the cat; do we simply not care about it for this purpose?

Yuma Desert Rat said...

Hello to all you Rver.s out there using Generators 5000 watts and up.
I recently purchased a new (7k surge), 6,000 watts generator at Home Depot. I think all of you guys have a similar sound problem with the engine noise after you put your new mufflers on, because yours run on gasoline!

My gennie runs fast and smooth and quieter on Propane, 80 decibels right out of the box.
Has electric start and regular pull start. got it for 850.00 and used a Lowes 20% off coupon which HD glady accepted, cost was $680.00 Here in Oregon propane is 1.50 less per gallon than reg. gas, oil stays cleaner (no carbon buildup) spark plug will last forever, everything but the tank came with it to hookup,You can use a small Coleman or standard RV LP tank, My gen runs 8 hrs at 50 % load on 20lb bottle. Hope, I helped someone!

Joel Jennings said...

Thanks Yuma Desert Rat. Propane si a great alternative. But. I think we would need some sort of carb conversion in order to use it. Just a thought.

Joel

Tony Tony said...

Hi Joel,
What a great post. I believe I have the same generator: Coleman Powermate pm0545007.01. I am not as handy as you though. I have a crazy question, pretty much I think I know the answer to it but I figured it will not hurt to ask. Can I pay you to build an identical pipe for me? I can buy the muffler to attach.
Thanks
Tony

Joel Jennings said...

Tony Tony,

Thanks for your compliment of asking me to build a pipe for you. Normally (which really means before having a 2 year old) I would say yes. But I just don't have time! Find a local welding shop and they will be happy for the business.

Joel

Brian said...

I just ran across this site while looking for some quieting techniques myself. I saw the posts from Anonymous and Cliff about utilizing plywood, etc. to completly deaden the noise. I was recently hired to build a noise decreasing "box" for a co-worker that turned out cutting the noise considerably. It is a stand alone outside an RV, so maybe not so much for traveling. However, I am now at the point where all I need to do is tap into the existing exhaust to lead a "smokestack" outside the box and keep the heat down. After I figure that out, I'll let everyone know how it turns out if you're interested. I'd upload some picutres of the box, but don't see how to. Anyway, just thought I'd let everyone know that it does work to box the generator in. The noise was cut more than in half (as noted by neighbors). The price for materials was about $100. Glad I found this site. There is little out there on the net to buy. This has given me some great fabricating ideas to finish the job completely. Thanks.

Anonymous said...

Actually, if you want to drop the noise another 50%, just run a vertical pipe up for your intake, like you did your exhaust. Just like air compressors, small engines make TONS of noise from their intake side. Try it. Get the intake as high, or higher, than the now-lifted exhaust...and you will drop 5-10 db more noise. It's just like porting the air intake of a garage air compressor outside through a wall...been there, done that, and was very glad how it worked out.

BTW...my intake and exhaust are siamese-clamped together, sticking up some 2-ft, with extender pipes and tractor flappers on top, should I choose to put them on, that can send both exhaust and intake to nearly 7-ft above ground...big quiet baby now.

Brian said...

I was able to re-fab some of the box I spoke about earlier. It now looks like a little house. All the deadining materials worked, and I was able to easily fab together an exhaust using piping hardware and a Briggs and Straton exhaust. The noise is cut considerably, and everyone is happy in the campground. I'd be happy to share pictures if I could figure out how on this site. I will gladly contact anyone who leaves info and send you some pics.

Chris said...

Thanks Brian,

I'm planning on making a noise reducing generator box myself. I'd like to see some pics if it's not too much trouble. I have a pretty good idea of what I'm going to do, but would like to get some ideas. My email is cjkarczmit@gmail.com

Thanks I look forward to checking out what you did

Chris

Will H said...

@ Pennywise

I'm using it for motorcycle racing too. Everyone in the pits has those little Honda EU units but it looks like they were discontinued . . . and 1000 for a 1600 watt version. I only needed to run tire warmers at 450 watts each so I bought two Harbor Freight 800 watt generators for 100 each. Being a motorcycle, of course I got replaced my stock R6 muffler which doubles as the Catalytic converter. I'm going to hook it up so both generators run through it and repot back.

Thanks so much Joel for posting this. what a great idea!

RGR the Electrician said...

Looking for Diesel Info, but found this. However, it gave me many good ideas and I will keep you updated when I come up with something! Good blog idea for quiet diesel...

Neil Harvey said...

I too have a Coleman 6250 Powermate Gen-set & have been embarrassed the few times I've had to run it since I got it in '05.
I was appalled at the $350 price tag for a Honda muffler, so started down the motorcycle muffler route when I found your blog.
I found a stock standard Kawasaki model KAW5340250 polished chrome muffler laying in a pile at a bike conversion shop,handed over 20 bucks and went to work removing the gas tank & heat shield.
I took off the B&S standard piece of crap, & cut off the flange leaving a short piece of straight pipe attached.
I don't have a welder(yet)so had my muffler shop guy do the following;
Weld a short piece of 1.5" OD heavy wall exhaust pipe over the short piece of pipe on the old muffler cylinder head flange.
Weld a flexible exhaust coupler to this piece of pipe.
Cut off the existing clamping arrangement piece in the inlet side of the Kawa muffler, and weld on a right angle bend & attach to flex coupler.
I drilled a 5/16" hole in the right hand vertical tube of the frame, and fastened through the existing Kawasaki mounting bracket.
I had muffler man weld a right angle bracket to the existing plate that was on the stock Kawa muffler, and I drilled a 1/4" hole down through the new bracket & horizontal hand rail of Gen Set & attach with 1/4" fastener & nylock nut.

Now I have a cool looking vertical chromed stack, that still fits in the back of my Ford Expedition, in case I need to run it over to a mate's place if he is outta juice.
The Kawasaki bike muffler is rated at 80 DB, - you can hardly hear any exhaust noise now - just have to put up with the single pot motor & generator noise, & recoil start rattle.(You pay peanuts, you get a monkey !)
I have about $65 invested in the whole conversion - and both my wife & our neighbors are impressed with the difference.
Unless you can afford a Honda set-up, I thoroughly recommend this conversion.

Anonymous said...

Great stuff, all of you guys! I was going to share something I was told about years ago for those permanent installs at home. There was a rancher who had an old Widdy generator that ran about 800 RPM loud with no muffler. He plumbed the exhaust out through the wall to a buried fifty-five gallon barrel in the ground with the outlet from the barrel shooting straight up 8'. I was told that all you could hear was a little puff of air coming out of the pipe. No worries about water running down the pipe because he said he put a little water in the barrel for absorbtion of the exhaust percusion. I know this doesnt help portables, or does it? Maybe a 5 gallon can half full water? Oh well, great ideas everyone! Thanks!

Anonymous said...

Hi
Very Good Idea i hope it will work?


EU2000I

Magnaflow Muffler said...

amazing post and i read a few comments which actually answered all my questions...amazing..thanks

Anonymous said...

Glad to see this post is carrying on four years later. It is encouraging. Right now, we pipe the exhaust from our 8kW B&S driven unit into the crock below the camp toilet. Works real nice in the winter. Summer time, not so much. Thinkin bout a stack through the outhouse roof. Maybe when the Cummins TD in the old Ram gives up the ghost....

Anonymous said...

Thank you all for this interesting and helpful thread.

Here is what I did with my China Honda Copy, 3.2Kw/4.2Kw unit:
1: Convert to propane. Ethanol blends in storage go bad quickly and mess up small engines. Propane engines and their oil last forever, and the fuel never goes bad. Less emissions and a cleaner spark plug, too. Not too difficult to do, and about $120 or so.
2: stainless Bellows flex connector so engine is mechanically isolated from the add-on muffler.
3: I used a muffler from a junked snowmobile.

QuickRick said...

So this weekend we had a 22 hour outage simply because of a breaker on a pole. Something has changed with our power company when simple resets take day when they used to take hours. My guess is that they have cut way back on help.

Anyway, I've discovered that our detached garage, with the windows open and the garage door shut is an ideal place to run the generator. Security is not an issue and fumes/heat are dealt with by opening windows. (and the attic fold down stairs open) The spiders and bugs are probably pissed off, but hey, I didn't invite them in!

QuickRick

Thomas said...

Dude i have a same generator with same problem, it we do with my 21ft long Lynx Prowler 5th wheel and over here in California if you are bit noisy in the parks the patrols kill you - so your blog can save my life! :)

thanks Dude!!!

Anonymous said...

I was told you could put steel wool or fiberglass mat in your muffler and it would cut down on the sound a lot, anyone know if this is true?

Anonymous said...

Brian,

If you have any pics of your enclosure, I'd like to see them.
Thanks.

It seems like there are some great ideas about the muffler part on here, either bike or car muffler, pipe, etc. and you are set. Now what about an enclosure for say, in the back of a pick up or in your yard?

I'm thinking of going with the two box theory, open ends pointing in opposite directions. Exhaust lead out the box and up into the air. I'll have to check on temps though, it would be nice to not have a fan, but will probably need one.

Anyone else out there go the whole nine yards with an enclosure too?

Anonymous said...

THanks for all of the info. It seems that there are some great options for the exhaust noise, but now what about the engine/alt. noise?

Anyone follow up with a nice enclosure?

Brian, do you have more info and pics of yours?

I'm thinking of going with the double box theory, insulated, and the exhaust exiting out and verticle.

Thanks for all of your help! and ideas!

Joel Jennings said...

If your muffler is designed for that, yes. Many offroad motorcycle mufflers or repackable. But I think a standard muffler, or a muffler from one of these generators is not.

bkc541 said...

I have a powermate 3750 and did the muffler and built a portable enclosure. For the muffler I simply made an adapter from the exhaust flange to exhaust flex then into a 4 cyl engine muffler. It is amazing how much difference that made alone.
The enclosure I made needed to be portable as I use it for camping. I simply cut 2 sheets ply in half (4x4). I used some kind of chicken wire I had around to form a cage to hold in loosely 2 bats of fiberglass insulation per side. On 2 panels I attached 2x4s on the inside edges running vertically.
So when you get where you are going you put the 2x4 panels across from each other and the plain ones on the other sides. Stand them up and screw through the plain edge into the 2x4, 2 screws per edge and its good.
I also have a high velocity 120v panel fan cut into one panel that blows directly at the intake.
that works so well for me because it's portable. Folks looking for more permanent fix could just beef it up if they don't have to move it.

Anonymous said...

Great to see this blog. I am waiting impatiently for my tri-fuel to come (possibly 1.5 weeks) and I am trying to get my ducks in a row. I have already purchased an Arrow metal garden box ($179, free ship) and 2 marine bilge blowers (12v continuous operation). So hopefully I can attach some reflective insulation to the box and cut a couple of holes for the blowers and of course the exhaust venting is my new concern, so this blog is getting the thought process moving again.

Anonymous said...

This blog is excellent. I just ran my B&S 5500 Storm Responder Generator for 1 full week after getting it 1 day before Hurricane Sandy destroyed my neighborhood in Staten Island.

Your blog gave me allot of great Ideas that I am going to try. First I will put a Tri-Fule kit on the beast for Natural Gas and then see about modding the muffler.

My goal is to reduce the noise by 1/2. That would make my generator much quieter than all those around me and much less of a target for looting.

I have 0 mechanical experience, other than changing my spark plugs on my Civic this summer. This should be interesting.

-Lenny

Anonymous said...

I have the same exact generator and I think this post will save my neighbors. I have no idea what I am doing so I will need some advice if you have some time. I started by trying to figure out how this piece that connects to the engine is called. I think is called the Exhaust Manifold.
Next step will be to find where to buy this thing and the pipe. My search took me to these links: http://tewarehouse.com/155-024-Sale?sc=2&category=1290202
http://tewarehouse.com/155-023-Sale?sc=2&category=1290202
http://tewarehouse.com/496750?sc=2&category=1290202
Sears manifold LH, Sears manifold RH and ADAPTER-MUFFLER. Which one of them will be the easier to weld to one of the iron pipes you used in your configuration?
After I get this I will move to the next step of finding an exhaust. If you know who makes the a quiet one please let me know so I can start searching.

Anonymous said...

I have a 5550 and (I believe) a 3550 Troy Bilt. Both have frames with pneumatic tires and handle. The 3550 stays at my property in the woods to power my 28' travel trailer. It needs to be quieter and I've been told that you can run the exhaust with muffler into water. Anyone tried this or know anything about it? Been told that even a 5 gal. bucket will work. Thanks

Kevin said...

I wanted to inquire about your post on March 2008 about the Muffler Support you designed for your rig. Would you please post the details and pics of how you supported the muffler to the engine. I'm no design engineer and want to avoid trying to "reinvent the wheel" with my own method which would probably be inferior to what you've already built. I like the design and if transport space was an Issue I see that the muffler can be unbolted and the remaining pipe appears to stay within the width of the wheels.

QuickRick said...


Kevin,

I guess that you were asking me but here goes anyway:
I used a muffler strap, the universal type with rubber strip and metal braket. The metal is bolted to 2 carburator return style springs and the rubber end holes are on the muffler mount as shown in the photo.
It works well during various power surges and start/stops not allowing the muffler to stress any exhaust components.

QR

Anonymous said...

I have a diesel that only puts out 79dbs already so the bike muff idea may be a way i can get even quiter than that while i'm at the race track camping with my 5th wheel. the exaust from the stock set-up comes straight out of the top of the unit already so to fab a support and aim an exhaust above the camper roof should be super easy. I'll post an update when i'm done

Patricia Christy said...

Ok, I'm a girl...but a very handy and mechanically minded one. I know nothing about cars or mufflers (nor did I know anything about computers, but I can take a laptop apart and fix or replace things to make it work). I just bought Generac 5500 W generator (I was using 2 -3 deep cycle batteries connected to an AV inverter for emergency power) but I'm ready for this new generator. I need to know how to make it as quiet as possible, because I live in a suburb that lacks tolerance for noise, even in emergency conditions.
I saw the initial posts for a bike muffler. But I'm not sure how to connect it. Do I need to find a car mechanic to do this right? Or can someone give me directions on how to do it myself. I'm pretty good with this kind of stuff. Thanks. P. Christy, St. Louis, MO

Bill D said...

Patricia take a look at my blog it shows how I quieted down my genny
"aquietergenerator.blogspot.com"

matt williams said...

All you guys seem like you have got the silencer thing figured out. I have a camp site where spend our summers boating on a river. Just wondered if anyone has tried running an exhaust thru water like they do on boats?

J Galt said...

My plan is to build an insulated box for it in my garage. I will add a car muffler welded on the gen exhause, and pipe it out of the box straight up into the garage attic, and out under the eaves. I will also run an air intake into the box, and run THAT up into the attic of the garage and out under the eaves.
I expect it to be VERY quiet.
It's a 7500 watt Diesel gen.
Thoughts?

Maxpower said...

The tricky part is the making the flanges. I thought of using a bike silencer myself. I'd like to fit one from a drz400 since they sound like a sewing machine. You did a clean job

Joel Jennings said...

Thanks Maxpower. The flanges weren't all that hard to make really. Just a hack saw, a grinder, a file, and a drill press. Took maybe an hour.

Anonymous said...

Call Ernie at Midas, 1604 DuPont Highway in New Castle Delaware. Just had my two Generac gennies, 5000 watt and a WheelHouse 5550 watt, completed and could not be happier.I did not have the time nor the tools (pipe benders, welders etc) to complete the project. Nor do my B&S 10HP motors have a threaded exhaust port. I had to rely on reusing the original flanges to remount the exhaust to the head.
I am a caterer and use the things to supply electricity for my outdoor events. As they come out of the box the things were so loud, it was embarrassing to have to start them up. They worked great, very reliable but LOUD, VERY, VERY LOUD.
Talked with Ernie at Midas and he made the entire project turn key.

Not only did Ernie make the project turn key for me, but the price was unbeatable. They handled all flange removal and welding onto new pipe, custom bending of pipe ,quality car mufflers provided and installed with hangers that have rubber bushings to allow movement, all welding , fitting, painting a flat black and final tweaking after installation. All for a great price. I am not disclosing the actual price because as a custom job, each will be different. But, believe me, the price is unbeatable. I looked up the price of parts, charges for having pipe bent, cut, welded etc. when I considered trying it myself.

I'm giving these guys a plug because they tackled a problem that I have had for a few years now and did a very good job at a very good price, same day service.

Rodney

Jak Manson said...

Great job on the muffler It looks really great and you did an amazing job. I wish that I could do that kind of stuff a little better than I do now. Thanks for sharing.

Anonymous said...

Good night, this place is an encyclopedia of information! I have an OLD- like 62 Coleman 5-k with a 10 hp i/c Briggs that'll rettle your teeth. I was looking foe a stiffler and thought $200 was a might stiff for a scilencer too. There were old golf cart muffelers that had a 3/4 inlet and an outlet about as big as your little finger; worked like an expansion chamber and the engines were Kohler 12 horse but they are long gone because they worked so well. The bike fix is a good one but the cooling air will be your killer. If you can rig up a foam surround on your recoil to a vent outside and have another one for the hot going out it'll be like an Onan in an R.V. that sucks the cooling air in the access door vent and blows it out the bottom along with the exhaust. The 55 gallong drum deal had water in it. I think it was in an od Popular Mechanics farm book. The genset was inside and the drum might've been just a 30 gallon but had the exhaust pipe unnder the water level and the outlet run up and turned away from the building for fumes sake. My Briggs is 36oo two pole and I have a Onan 2.5k 4 pole/1800 r.p.m and the slower the better. Added electric start to the Briggs because I am getting too geezerish to be yanking on that baby. Will try a auto muffler because I have the 3/4 threaded female in the engine blo0ck so it'll be an easy fix. Yall are great and better scientists than you realize. Common sense goes farther than a shingle to hang out by the road. Keep on using your heads. You're getting cheaper and better all the time! (me)

Anonymous said...

I am very interested in the solution of running the exhaust into a 55 gallon drum buried in the ground. My neighbor has a generator running and will let me build a silencer or him. So, does the exhaust enter the drum from the top? And extend into the water? What sort of pipe goes out of the drum? Is there any problem having the exhaust leave the generator and then turn down?
Thanks.