I've got some conflicting info recently. One dealer told me to always slow the engine all the way down at idle because it's easier on the engine. Another dealer told me to always shut down at full throttle because when you slow the rpms the engine backfires more and that's hard on the head gasket. I'm no expert on small engines but would really like to know what the truth is.
Engine RPMs up or down on shutdown?
srheinz
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Yea! I went back and reread my Kohler Manual. It states 1/2 throttle or higher. I take heed in the washing of the cylinder when stopped at higher rpms. So I tried idling at low idle before stopping. No backfire! I'll play with that for a while.
Thanks!
ms
Couple points...
I do not see any benifit to letting it idle for an extended amount of time before shutting it off. Just bring it down to idle and turn it off. (If your manual says 1/2 throttle, then follow that)
Also, any engine thats at least 10 years old has a fuel shutoff solenoid in the carb. When the key is turned off, the solenoid blocks the fuel from being sucked into the engine. This takes care of any fear of cylinder wash and lessens the chance for backfires.
The reason you get a backfire, is that there is fuel that was not ignited due to the ignition being shut off and then its spent into the hot muffler. Thats where you get your "bang". Its not in the engine, and you can't "blow a head gasket" due to a backfire after turning the key off.
I do not see any benifit to letting it idle for an extended amount of time before shutting it off. Just bring it down to idle and turn it off. (If your manual says 1/2 throttle, then follow that)
Also, any engine thats at least 10 years old has a fuel shutoff solenoid in the carb. When the key is turned off, the solenoid blocks the fuel from being sucked into the engine. This takes care of any fear of cylinder wash and lessens the chance for backfires.
The reason you get a backfire, is that there is fuel that was not ignited due to the ignition being shut off and then its spent into the hot muffler. Thats where you get your "bang". Its not in the engine, and you can't "blow a head gasket" due to a backfire after turning the key off.
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Rm25x is correct, backfires don't cause blown head gaskets...and any competent mechanic should know that.
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