Backfire

[Dingo]

i just bought a new mower and it backfires everytime i shut it off. Its a exmark 19kaw. anybody have this problem too? What should i do about it?

[Guido]

I had the same problem with my 14hp Kai on a 93 exmark 48&quot; Never did figure out what caused it though..??? Sorry!!<p>----------<br>&quot;guido&quot;<br>David M. Famiglietti

[sparkspride]

I have had these problems with kohler motors also. The reason is the piston clearance is a few thousands less than most of the older mowers. Fact: Make sure that you idle your mower down all the way before you shut it off. If you don't there is a chance that you could over torque your rod and have to have a rebuild job that could happen everytime you shut your mower off. These high compresion motors really need to be idled down. It will save your motor

[Richard Martin]

In addition to what Sparkspride wrote you should also allow the engine to idle for a minute or two before shutting it off.

[DMC300]

LETTING THE ENGINE IDLE WHILE YOU LIFT YOUR TAILGATE,START YOUR BLOWER,ETC...JUST A FEW MINUTES WILL HELP.<p>----------<br>DON<br>LIANNES' MOWING

[Green Acres]

You should let every piece of equipment idle for a few minutes before shutting them off. It's kinda like when a human runs a mile they say it's good to walk for 10 minutes afterwards to let your body cool down. Hope this will fix your problem.

[DTM65]

I read in the Kohler manual that for engines that are not equipped with a shutdown solenoid, you have to let them idle before you shutdown to avoid the backfire problem. <p>Some engines have them, some don't.<br><p>----------<br>D. Tom<br>

[farmall]

The reason the engines backfire is this. In order to help the engines to keep from running lean and burning pistons or valves, they run a little rich in the fuel mixture. When you let them idle, this extra gas builds up in the muffler and when you shut the engine off, there is actually a heat soak for about 20 seconds. This means that the muffler gets hotter after you shut the engine off, than when it was running. It gets hot enough to autoignite the fuel mixture, thus causing a backfire. I believe the exmark manual recommends shutting them off from half throttle to alleviate this problem. This richens the mixture in the muffler enough that there is not enough oxygen in the mixture to autoignite. No backfire. The backfire should not cause any problems inside the engine, since this all happens in the muffler.<p>hope this can clear some confusion up<br>

[Evan528]

all of my kawisakis and kohlors backfire if i dont let them idle for a minute or so. im very impatient doing this but if i dont my 25hpkohlor will backfire so loud it sounds like a car exploded!

[Bobby]

I had the same problem wit my 25-Kohler.The distributor advised me to shut it down at half throttle. It works.I had a 14-Kohler that blew up three mufflers. The third one cost 140.00 with the (special mounting kit.) They were under warranty. <p>----------<br>Bobby <br>Ft Lauderdale<br>

[osc]

Actually, I had a kohlor rep tell me to idle the engine all the way down for a minute &quot;and then&quot; rev it to half throttle just before shutting off. My Kohlor will still backfire if I shut it off at low idle. If do ot the way the rep says, then I get no backfire. None of my Kaw's seem to backfire.

[MowerUp]

I have a 25 hp Kohler that does this. My mechanic told me to push it back to half throttle and cut it off. THis works!<br>

[cantoo]

Kohler's manual on my 20 hp says to shut it off at 1/2 throttle... If in doubt read the manual for shut down procedures. I'm not sure on the Kawi's

[Charles]

My new 23 kohler. Backfires no matter what you do. Not everytime but most of the time. I idle it down and it still backfires. But was told this was natural.

[McLawn]

If you shut down at 1/2 throttle you will not have a problem.

[Fishbige]

As soon as you turn the key off, push the throtle wide open & it won't backfire.

[Alan]

For what it's worth, my 25 Kohler (Exmark Lazer Z) would backfire like you describe. I switched to Amsoil synthetic oil and the backfire stopped. I theorize that their claims about running cooler on synthetic oils is true and the reduced temperature makes the difference. Incidentally, the synthetic oil is getting once a season changes and is not cooking into a thick black goo in 250 hours of use. Guess it stands the heat just like they claim too.