Grasshopper 718K quits running when hot

Wayne Saak · Jun 20, 2014

My Grasshopper 718K with Kohler engine quits running when the engine gets hot. No spark. It will start back up again when the engine cools. Anybody have any suggestions as to what I need to fix?
Thanks

rrobert · Jun 20, 2014

Try a new sparkplug first. More than likely, the coil is faulty.

More than likely the coil(magnetto) is bad. Most coils quite working and that is it. The other 15% of the time, they quit when they get warm and then work when they cool down only to quit when they get warmed up again.

Is it a magnetto or a car type coil? If changing a car type coil, I would also change the points and condensor.

joe csuti · Jun 20, 2014

The kohler ch18 eng had 2 different style ign systems avail,both systems use 2 modules(coils),the first system is a fixed timing cd system,the second system has a sam module for changeing ign timing according eng speed/load & also has 2 ign modules which are different than fix timing modules however one thing both systems share in common is an oil pressure sw that will kill eng ign due to loss of oil pressure,disconnect oil pressure sw & see if that cures problem,if it does then problem in lube system,possible problems in lube system-bad pressure sw,plugged/restricted filter,worn oil pump,internal wear in eng causeing loss of pressure when eng gets hot,wrong wt oil.

Wayne Saak · Jun 20, 2014

It has a mag and I thought that might be the problem as there is no spark when it is hot. Started to take the outside covers off but it looks like you have to pull the engine to get the cover off that is over the mag. Thanks for the replies.

joe csuti · Jun 21, 2014

If you haven't done so already goto link below & download/save the service/repair manual for your mod eng.

Regardless if you have the fixed ign or the sam module ign system(smart spark) the problem may be in mower ign sw,safety sw's or wiring harness on mower,both systems have a seperate ign module for each cyl,while it is rare that both coils will fail at same time it's not unheard of.

Disconnect oil pressure sw(if eng has)if that doesn't cure problem,locate ign kill lead in eng wiring harness(usually a white wire)and disconnect from mower wiring harness,if that cures the problem with the possible exception of kill lead shorting to sheetmetal/block on eng when hot problem in mower sw's/wiring or possibly a bad sam module as you have yet to determine which ign system on eng.
kohler

rrobert · Jun 21, 2014

yeah, I agree with Joe. Do some more testing. If you have two coils, see if the other coil has spark.
Check safety switch wiring. I know my Ch22 will shut down if the Ebrake is on and I try to go forward.

ztrmowers · Jun 22, 2014

replace the modules

Fred Swick · Jun 22, 2014

Have you replaced the condenser?

greygoat · Jun 22, 2014

My specialty is Wisconsin Engines..but it"s
common, on 1 cyl"s, 2 cyl"s, V4"s, Wico or
Fairbanks-Morse magnetos, that, when you shut
down a hot engine, and it won"t restart until
cool...that the coil is failing

Wayne Saak · Jul 2, 2014

I replaced the mag and that seems to have fixed the problem. Thanks for the help.

Grasshopper 718K quits running when hot

Wayne Saak

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rrobert

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joe csuti

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Wayne Saak

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joe csuti

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rrobert

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ztrmowers

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Fred Swick

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greygoat

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Wayne Saak

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