1862 With a Kohler M18 question

[cphipps]

Does anyone have the ohm check procedure for the ignition module on this unit. The manual pictures are not very clear. The engine shut down after about an hour mowing. I noticed the spark looked weak. Went out the next morning and it fired right up. Also when you shut it down after running hard it sounds like the gas in the carb is boiling. The engine does not seem to be overheating. Thanks
Chris

 

[mgwin]

Chris,

Is this what you are referring to?

 

[mgonitzke]

That's not going to work for a magneto ignition module.

Chris, go to Kohler's website and download the service manual for the M18. It should have the method for checking the primary and secondary resistance of the magneto.

It's going to be really difficult to check this while the engine is hot. If you put a spark tester on immediately after it dies and there is no spark, you need a new magneto. In my experience, the spark looks weak on these all the time even on a good one.

 

[cphipps]

Thanks Matt, That's was exactly my plan. I looked at the manual and they refer to some photos that don't show up well enough to see. Did you have any thoughts on the boiling sound coming from the carb at shut down? I actually poured a little gas in the carb one time and it sounded like it was boiling. The tractor runs fine most of the time but if you shut it down hot and let it sit too long and try to restart hot it acts like its not getting gas.

 

[cphipps]

Matt,
Also, I was looking at the diagram for the spark tester, I'm assuming you need to ground the tester correct?
Thanks,

 

[mgonitzke]

Whether or not it needs to be grounded depends on the type. If it is inline, there is no ground. If it is bypassing the plug entirely, one end will have to be grounded or there is no circuit to complete.

As far as the boiling gas, is there a gasket installed between the carb and intake manifold? In my experience the carburetor and intake are fairly cool while the engine is running due to the atomization of the fuel reducing the temperature of the intake air. Are you mowing at full throttle? Is all the the tinwork around the engine installed, and are the cooling fins on the cylinders clean? How about the flywheel screen?

If it is boiling immediately at shutdown,especially after it dies, I'd be suspicious of vapor lock causing the engine to die.

 

[cphipps]

Thanks again for the help, all of the above have been checked except for the gasket. I work on heavy equipment for a living and have been fooling with the older cubs for a while but the boiling gas kinda had me puzzled. Really appreciate your help.

 

[cphipps]

Thanks for everyone's help. I found the fuel shut off valves on both sides clogged. I cleaned them out and it seem to run well. Hopefully my son will get the mowing done today. I will update you all if there are any further issues.