I bought a Coleman Powermate 5000 a few months back.
It works fine for the ocasional location welding I need to do.
It only has to power my inverter.
My only problem is the noise.
It has this tiny little spark arrestor, and no real muffler.
I am hoping that one of you guys has successfully added some kind of
muffler from a moped or small motorcycle.
The engine is a 10 hp Tecumsa Sno-King engine as used on snowblowers.
I am looking for a simple cheap solution, but I don't know enough about
small engines to know if the muffler provides some kind of back
pressure to the engine.
I used $19 muffler from advanced auto on my home made welder. It does
help allot with the noise, but you will need to know how to weld to
set one up. One thing to keep in mind is most of the inexpensive air
cooled engines fire on every stroke. If you turn the engine off at
full speed then you will fill the exhaust with a good mixture, if you
start very soon after turning off, you will make the guy next to you
look up a bit.
Ernie Leimkuhler wrote in
You can probably get away with any muffler you want. That's got a 4-
stroke engine. Most small engine/ tractor mufflers don't have any
noise material packing though.
The last decent muffler on my 16 HP Techumseh powered welder, the can
was about 12 inches long, by 5 inch diameter. It was an orig
equipment off of a good garden type tractor. It had a bologna cut on
the outlet (diagonal cut on the pipe). That might have helped it
sound better too.
wayne wrote: (clip)It does help allot with the noise, but you will need to
know how to weld to set one up (clip)
Ernie, in case you feel you need help with the welding, don't hesitate to
e-mail me. I've been welding for several months now. There may also be
others in this group who have developed the kind of experience which you may
If you're only concerned about the noise bothering you, then the cheap and
easy way is to get the generater behind something. Campers regularly put the
generater behind a convienient bush, and throw and old blanket on the bush,
this works pretty good.
If you're concerned about the noise bothering others, or want a more elegant
solution, then you can use just about any small to medium sized muffler
available. As others said, just support it well so as to not to stress the
pipe coming off the head. On a little engine like that you won't be adding
an amount of backpressure that will harm the engine.
For quiet, I often find that a car muffler (and whatever adapter is
needed to get the car muffler attached to the small engine exhaust) is
more effective than many of the "small engine mufflers", which are
simply too physically small to be very effective at quieting. I figure
if it will let a 4-8 cylinder car engine breathe, it can't be
overloading a one or two cylinder small engine with excessive
restriction/backpressure. It's not a two-stroke, so there isn't much
"tuning" of the exhaust going on.
You want to support the muffler so that the engine exhaust port is not
carrying the weight of the muffler. Your standard Briggs & Strattion
exhaust port is a standard pipe thread (or was the last time I fiddled
with one), so plumbing your way from the exhaust port to the muffler is
not too difficult.
Ernie's engine is a 4 stroke, but it does fire on both power and
exhaust stroke. The smaller air cooled engines use the crank for
timing. The problem is often the engines will fire (depending on
valve/ignition timing Fire before TDC and the exhaust valve open till
TDC) with the exhaust valve open some, if there is any fuel in the
muffler it is going to ignite. Larger water cooled engines use the cam
for ignition timing. The cam runs at half the RPMs of the crank, this
will only fire on the power stroke. Now I realize many new engines are
not fixed to the cam position but that means nothing here
OK... we're on the same track here.
BTW, I enjoyed viewing the spool gun you engineered! You've got more
patience than I've got! :)
Wayne's spool gun:
I will say that when I put my home made spool gun
I have an old Wisconsin twin fed into a junked muffler found at a muffler
shop. The volume indeed seems to do the trick. The inside of this old
muffler is rotten but the outside is sound.
It worked for this old Hobart. Now it is no louder than a residential
$505 brand new, including tax, at Costco.
So far my only complaint is the noise.
I just picked up a length of flex exhaust hose and a muffler for a Geo
Metro (it was the smallest muffler the parts place had).
I have to make up a mounting flange for the exhaust port on the engine
and fab an elbow to get the exhaust pipe located right.
So I successfully mounted the new muffler last night.
I bought a Geo-Metro muffler for $30 new and ended up using some pieces
of fancy stainless flex tubing I had from school.
I also welded up a custom stainless steel flange and short 90 deg elbow.
One of my students last quarter works for a hose shop that makes up
those fancy stainless steel flex hoses with the braid on the outside.
I had several practice pieces of his and simply added them together.
It all worked very well.
The generator is still loud, but now it is more like a normal lawnmower.
When I shut it off I did get a substantial backfire from the muffler.
Kind of startled me.
One used 1.5 KW generator that had sound proof housing made of plywood
with rockwool insulation. It was so quiet couldn't hear it from 20 ft.
We even shoot mopic with sound record without noise problems. For this
to be practical must have electric start.
This crude drawing showes box layout looking at frount side.
X M X
X X X
X X X
X X X
X I X E and G X
X X X
X X X
X X X
E = engine B&S
I = intake compartment
G = generator
M = Muffler compartment
There was 2 ea. 4" Dia. air intake grills on back side of air intake
The engines air intake/recoil starter was aginst rock wool insulation
and bukhead for intake compartment so it could draw cooling air
through hole. Carborator was on frount side so it could be accessed
through door for E & G compartmet. Door was sheet metal with rock wool
Muffler compartment was sheet metal with rockwool insulation. Exhaust
left engine through flex tube through top of E&G compartment near
back edge into M compartment. Muffler layed on rock wool. I never
opened the muffler but it looked like glass lined pint paint can. The
frount of E was open and located at about middle of top.
It used outboard fuel tank and had external oil tank.
With the engine having spark on the exhaust stroke it will be loader
than an engine that uses the cam for timing. The other problem with
the less expensive gens is that they don't have idle down, when you
shut off the gen it is winding down form 3700 RPMs this loads the
muffler with an air/gas mixture, that muffler is HOT so it will go
bang. Its a big help in the noise department but does not pure like a
new car. Most of those small mufflers just do a steady burn as the
engine runs, your large muffler "stores?" alot more gas/air mixture. I
always get a kick (not always) out of snow blowing in real cold
weather in the dark of night and see the flames shooting out of my
snow blower. When you shut them down if its dark out you can see the
Yes the engine Ernie has is a four stroke, but it does fire on every stroke.
The small air cooled engines timing is run off the crank not the cam. (The
flywheel provides the power for the spark) That fires the engine on both the
power stroke and the exhaust stroke. This can cause problems if any gas is
in the muffler. Most larger water cooled engines fire only on the power
stroke, they also use the battery to power the ignition. Most water cooled
engines use the cam which runs at half the rpm of the crank. Now newer cars
use more than the cam.
Wayne Makowicki wrote: Yes the engine Ernie has is a four stroke, but it
does fire on every stroke.(clip)
I don't know whether this is still true, but I recall my Honda 4 cylinder
fired the cylinders on pairs. One was on compression, and the other on
exhaust. The plug on the exhaust side acted as a spark gap in series with
the active plug, enabling partially fouled plugs to keep working. (A spark
gap prevents the energy from bleeding off during the rise time of the
voltage.) It also allowed the engine to get by with fewer ignition
Ernie, the tail pipe extensions for VW cars are actually small mufflers. I
have successfully used them to reduce the noise on small engines. They are
pretty cheap from JC Whitney, and probably available from your local auto
parts store. You would need to make an adaptor to fit them to the engine,
but shouldn't be a problem for you.. Good luck.. Jim
I have the exact same unit. Good generator, powers most of my house in an
emergency. That engine is *very * noisy though.
I went to the auto parts store and got a length of 2-1/2" stainless flex
tube for exhaust use and an extension pipe to fit the flex tube. Welded the
4" long extension pipe over the outlet of the stock muffler and attached the
pipe to it and any old muffler on the other end. This allows me to put the
generator in the garage and exhaust it outside. The exhaust is now fairly
quiet but the engine block is the loud part now. Seems to be valve noise
from the solid tappets.
The engine also wear was more than expected. We were without power for one
24 hour period and ran from the generator. Luckily I had my speedboat
trailered in the driveway with 30 gallons of gas in it. I had to add oil to
the generator several times when the low oil switch kicked in. The
temperature was in the 90's and with the garage door almost closed, must
have been 110 deg in there. Engine still runs well but is getting even
noisier. All things considered, next generator is going to be an overhead
valve with pump lubrication (not just splash lube).
Still, 5KW is a good power level to have. Darn handy to run the MIG from
too. Far more consistent welds than running from the poor electric in the
You are going to get one hell of a lot of vibration from that unit so
plan accordingly. Another issue is that it doesn't have an auto
throttle or at least the rig that they use is quite poor. I would be
very hesitant about running anything drawing a lot of start up current
or intermittant use from it or you might just burn out whatever you
have running. I found this out the hard way during the ice storm of
98 in NY when an identical unit I had running backfeeding the house
via my welding circuit seized the gun on my furnace which spiked and
cooked everything in my house that was plugged in and had transistors.
No it wasn't a case of overload just that the machine couldn't catch
up with the requirements that I had been happily meeting for days with
a 3250 watt Sears( Generac) with the ohv engine. It simply welded the
brush to the motor on the furnace and dead shorted the system, caused
a small fire in a GFI as well. I had a hell of a time starting the
thing to boot, lifting all 200+ lbs of it off the floor to get it
running. If I was going to use it with a welder I would keep that idle
cranked WAY up so you don't suffer something similar' lights and small
draw appliances don't seem to matter.
I never had one hesitation from the little Generac and I still have
it today running as good as the day we got it. I don't mean to rain
on your parade but merely reflect on my personal experience with an
identical unit. I guess thats the difference between a $400 Coleman
and $900 Generac and this is one of those cases where its justified
for those who can afford it. If I was going to muffler that rig, and
it is VERY loud I would take into account for all that vibration and
the way it wanders about when running on a concrete floor.