18hp kohler doesn't want to shut down

old diesel · Sep 27, 2015

have power king with 18hp kohler engine. it runs well , but lately when I switch it off it makes a shuttering sound, vibration, spark knock and almost feels as if it is trying to run backwards before shutting off. what is going on? thanks for any comments.

joe csuti · Sep 27, 2015

Several possible causes of problem:
1-passages between cooling fins plugged/restricted due to dead grass/leaves & eng running hot.
2-not running eng 1 min/more at low rpm before stopping to allow eng to cool down.
3-fuel shutoff sol stuck open or not closeing all the way allowing eng to suck fuel out of carb while slowing to a stop.
4-float valve in carb leaking.
5-contacts in ign sw for ign kill circuit going bad or complete sw worn/going bad & needs replacement.
6-carbon buildup in eng causeing pre-ignition/run on

MNGB · Sep 27, 2015

I agree with Joe, but you can forget about #3 your engine is a K361 and has no fuel solenoid valve, first thing I'd try is a can of Sea Foam in the gas tank and try running some 91 octane gas next check the switch and have clean cooling fins on that engine is very important remove the top cooling tins and clean the cooling fins, also check that the right spark plug is installed it should be a Champion H10C.
GB in MN

jeffcat · Sep 28, 2015

If I may add one more to the list. Crappy gas will not help either. Something with very low octain and then a hot spark plug end acts like a model airplane glow plug engine. Have also seen heavy carbon do the same. Take your air cleaner off after you have mowed a little and pour a little water down the carb as you jazz it a bit to keep it running. The water forms hot steam and scrubs off some of the carbon. Checked it many years ago as a kid on an old Briggs and then pulled the head off. It really works.

old diesel · Oct 2, 2015

finally able to go down to shop and do some trouble shooting. things that helped , lowered timing just a bit, idled engine down some, run engine at idle some before shutting off, but for my engine at the suggestion of a local friend I bought a cold plug for the 18 hp. it seemed to run smoother and definitely shut off better. thanks for all the hints.

18hp kohler doesn't want to shut down

old diesel

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joe csuti

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MNGB

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jeffcat

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old diesel

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