18hp kohler backfire

bodydropped72

Hey all finally got my cart going today with an 18hp kohler motor I picked up dirt cheap. The motor was originally used for a generator. I had the crank turned to accept a Polaris clutch. What are my best options to quiet this thing down, keep good back pressure and keep it from backfiring? Thanks


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pachanga90

Do you have the original muffler,or access to an old lawnmower muffler from a vtwin?You can mount it where you want and build pipes to it.I wouldnt run it much without anything since valve bending will occur.Hope this helps.

slonomo

Backfiring can be caused by a lot of things, get your exhaust on and see what it's like then. Running lean, exhaust leaks, valve lash all possible causes.

Do a quick search on exhaust or muffler and you'll find tons of ideas. If you fab your own, make sure you use very thick steel flanges that are true on the mating side and have nice wide flat mounting ears. Nothing like a crookedly mounted exhaust to cause problems.

bodydropped72

I have exhaust on it 2 to 1 into a flow through dirt bike muffler. Not sure about my carb you can see it in the picture above. Like I said this was for a generator and designed to run at a set speed. There's no air fuel mixture screw just idle adjustment. Any recommendations?

slonomo

What kind of dirt bike muffler? Can't really judge the sound by a description, but I'd use more of a small automotive type muffler if you can fit it. If not, use one that has packing material in it. Either way you go, it's going to be much louder than a stock golf cart muffler. I've seen some guys use atv muffler's and they sound pretty good, sound like a stock atv.

Can't see the carb in the pic. Guessing it's a stock carb. Alot of vanguard guys use the 2 barrel carb conversion.

http://www.buggiesgonewild.com/big-b...rrel-carb.html

http://www.buggiesgonewild.com/big-b...uard-23-a.html

Not sure if you can do the same mod on a Kohler?

Streetbu

I kinda doubt it's caused by the exhaust or lack thereof, More noticeable yes, but if it's backfiring thru the exhaust it's most likely running lean, possible partially sheared timing key but I doubt it. Either make your carb adjustable or get a different carb. Like you stated, it was designed to be run at one rpm, not varied. So no matter what you know you will need a carb so get that out of the way and it'll probably be fixed.

dropzone

It's not unusual for a small engine to back fire with out an exhaust muffler on it. They need some back pressure to function correctly. Considering the engine is set up for a generator with a set RPM the gassing on it and letting off causes it to load up on fuel causing it to load up and burn as you let off the gas. The Part Number for the Carburetor that fits that engine is 24-853-03-S. There are only two adjustments on these Carb's the idle and slow idle or idle air mixture. The idle air mixture is probably covered but it is just to the right of the fuel solenoid behind the bracket.

bodydropped72

Mine says 24-053 43 and I don't see any idle/airscrew just plugs near that area

pachanga90

With an open port or even an open pipe,it will backfire,moreso without anything at all on it.You shouldn't run any engine with the port directly open to the air,even a short pipe will prevent sucking cooler air in as the valve closes,causing a bent valve.seen it too many times,its more than likely to happen.Carb adjustments will need to be done after the exhaust is done,since a free flowing exhaust will flow differently and it will likely still backfire occasionally on deceleration or shutdown. My oppy would backfire on shutdown even after idling with the stock exhaust,it really does on decel with an open header,and its over 2' long.

dropzone

It's a slow idle adjustment behind the plug. It's not going to do much adjusting it. There are no other adjustments on these carbs. I'm looking for an alternative that will fit the CH20 I have with adjustments but haven't fount anything.