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Hi,
RE: 2009 Ariens 42" 19hp Kohler
My problem is that this mower runs fine, but once I turn it off, it backfires so loud, I need earplugs!
It's done this since I bought it. The only thing that helps is when I let it run at idle speed for a few minutes after mowing, otherwise, Kapow!
Any help appreciated.
Wendy

dont worry about it...its normal....by the way this is the craftsman forum:laughing:

LT1045wrh said:

Hi,
RE: 2009 Ariens 42" 19hp Kohler
My problem is that this mower runs fine, but once I turn it off, it backfires so loud, I need earplugs!
It's done this since I bought it. The only thing that helps is when I let it run at idle speed for a few minutes after mowing, otherwise, Kapow!
Any help appreciated.
Wendy

Click to expand...

Its running rich...see that the throttle is closed during idle time.....or shutoff time...
Running rich is also running cooler...VW was like this, no problem when gas was plentiful...
The thing is, is it too rich ??>>>and what can be done , that is bottom line beneficial.

Idle down for 30 seconds before shutting mower off.

It may be running rich, however, I would check the fittings on the exhaust. My VW backfired terribly, and it took many hours to eliminate all other causes. It turned out to be a leak in the exhaust fitting.



And this thing made a BANG!

A couple things could cause it...
Carbon build up, that will increase the compression ratio and that will require a bit higher octane...
Very lean mixture will run Hot and cause exhaust valves to run hot enough to ignite fuel mixture as engine is shut down...

Kohler engines that I have had all ran better with higher octane fuel, since you say it has always had this problem, yours may also run better with higher octane... it will only cost you around 15 cents a gallon to try it... Run a bit of premium to see if it still backfires...
You will want to stop having this problem because it will eventually destroy your muffler... and it is not good for your hearing... :smile:KennyV