What causes the engine to backfire when I shut it down? It only backfires once and usually just as the engine stops turning. It is about a 6 yr old Craftsman DGT 6000 27 hp Kohler twin , It was my late Fathers tractor.
Unburnt fuel gets sucked in from the idle circuit as the engine slows to a stop and ignites in a hot muffler. Try shutting down at 1/4 to 1/2 throttle. That normally helps on Kohlers.
Engines with a carb fuel solenoid should be shut off at higher speed.
The plunger blocks the main jet, preventing fuel flow through the carb and the few additional seconds of engine rotation, with the carb "gulping air", purges the fuel vapors out of the exhaust system.
Thanks for the information, that was what I was doing, I will start shutting it down at half throttle. My X300 doesn't care what position the throttle is in.
As has been advised on this forum many times, I throttle my Kohler engine down to its lowest idle speed for a few seconds before shutting off. Never get a backfire.
I second, Engine and Bill's reply.
I also follow the suggestion of idling down for a bit then shutting down the engine while simultaneously opening the throttle to about half travel. Usually works just fine.
Hey! Hey! Hey! You guys are defeating the purpose of owning a Kohler engine, with its world-famous "backfire-on-shutdown" feature! It was carefully engineered to frighten the neighbor's dog and flush critters out of the barn.
My Kohlers (I have four) also signal the wife that I've finished my chores and it's time to put supper on the table.
You can now purchase an electronic "backfire" generator. It is hand portable and can be adjusted to give a pop (like a cork) or turn it up and put a 12 gauge shotgun to shame. It was inspired by the "electronic bugle" that was developed for funerals with military honors. It seems that there aren't enough "bona fide" bugle players now days to do the real deal......so they have come up with a "fake bugle" that has a speaker in the horn and is powered by batteries. A digitally recorded rendition of "Taps" can be played on demand and all the "player" has to do is hold it and pretend to play. So if you miss the famous backfire, stop fretting and get your "electronic backfire generator" today. :^)
Briggs also backfire. if it's got alot of hours on it, it may be carbon deposits hot enough to light off the munute amount of gas fumes left in the comb chamber. I would think idling 30 seconds or so would help.
My CC with briggs single els always backfires in the summer unless I let it idle for a minute or two. I usually blow it off and after I'm done blowing the dust and grass off it's cool enough and don't backfire. It has done it since new. I have 160 hrs on it now and it will still do it right after mowing in hot weather.
I have had brand new briggs pop right out of the crate. When I had to rejet the Kawi V twins, if they popped after rejetting they were too lean. If a Briggs pops, I will back out the mixture just a little bit till she won't pop every time. Then the short cool down works great. Of course thats if its a low hour engine with no carbon.
Thanks deeredoctor. I'll look for the mixture screw and rich'en it up alittle see if that helps....
im with javert about the word famous kohler back fire, my grandpas kohler powerd massey ferguson does that everytime you shut it off medium or low throttle it'll allways do it, and one time the neighbors across the road took their little pug for a walk when i shut off the lawnmower it backfired so loud the dog nearly flew in the ditch from the scare,lol.
btw, i have 2 different lawnmowers that i take care of for my grandpa and me, my grandpa owns a 785 acre cash crop farm and i have 10 acres that i take care of with my yard man et1238 and massey ferguson 2514H growing veggies and fruit
The funny thing about the Kohler backfire to me was this: Anyone that knows Kohler knows they have a detailed procedure for everything. Lack of engineering was something you could never say about Kohler. This topic seemed to come up inevitably at the update seminars. The Kohler training guy after going over the "proper" shutdown procedure to lessen the backfire basically gave up after a bit of interaction from the techs. So the topic basically ended with a bit of laughter and a have your customer do what's best for them. So if you needed to shut it down with your left foot in the air and the throttle at medium speed for seven seconds- then so be it....
maybe ill try that tomplum, lol,