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Ask Hank F. Your Own Question
Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 14621
Experience:  Certified on Onan and Generac generators
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I have an onan microlite 4000 model k that will run for

Customer Question

I have an onan microlite 4000 model k that will run for about 15 minutes and die. Has no spark when hot. Replaced coil and start/stop switch. Gets plenty of fuel, I replaced the start/stop switch because in notice complete no spark when in the start position but when I release it has moderate spark, but not enough to run. Any suggestions?
JA: Do you have fuel in the tank? If so, is the shut-off valve open and the fuel clean?
Customer: Yes good fuel and fuel flow.
JA: Do you plan on doing the work yourself?
Customer: I'd like to if possible
JA: Anything else we should know to help you best?
Customer: I own an auto repair shop with good mechanics but not used to small motors
Submitted: 5 months ago.
Category: Small Engine
Customer: replied 5 months ago.
I was in error, It is a Model H
Expert:  Hank F. replied 5 months ago.

If you are not getting any spark, and have already replaced the coil, the magneto is most likely bad.

Customer: replied 5 months ago.
It runs fine when cold for 15 minutes. I thought a magneto either works or doesn't.
Expert:  Hank F. replied 5 months ago.

No, a magneto is perfectly capable of running great for 10 - 20 minutes until it gets hot, then breaks down.

Customer: replied 5 months ago.
Is there a way to test it?
Expert:  Hank F. replied 5 months ago.

Yes, you can test the voltage coming out of it.