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Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 15264
Experience:  Certified on Onan and Generac generators
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I have a gas Onan in a class motorhome. after 15 minutes it

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I have a gas Onan in a class B motorhome. after 15 minutes it stalls. I have replaced the fuel filter and changed oil.
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: for over a year
JA: Do you plan on doing the work yourself?
Customer: depends on what the problem might be
JA: Anything else we should know to help you best?
Customer: i don't think so

Hello, my name is ***** ***** I am going to assist you with this.

What is the full model number of the genset?

While it is running, is it running smoothly, or is it surging?

When it shuts down, does it just shut down like someone turned it off, or does it start running rough right before it shuts down?

When it shuts down, will it start right back up, or does it have to sit for a while before it will restart?

Hank F. and other Small Engine Specialists are ready to help you
Customer: replied 2 months ago.
Yesterday it ran great then shut down like someone turned it off. It has to sit awhile before it restarts.

As per our phone conversation, here is how to test the coil and magneto.

Start the set and let it run until it shuts down.
Remove the control panel to access the coil
Pull the white wire off the coil.
Pull the spark plug wire off the spark plug.
Set your meter to ohms.
Connect the black lead to the coil mounting screw.
Connect the red lead to the terminal you removed the white wire from.
You should get a reading of 0.5 ohms.
Now connect the red lead to the spark plug wire.
You should get a reading of 1,100 ohms.
If either reading are out, the coil is bad.

Now set your meter to ACV.
Connect the black lead to a good engine ground.
Connect the red lead to the white wire you removed from the coil.
Press and hold the start button for about 5 seconds.
You should get a reading of 15-60 VAC.
If you get less than about 15 VAC, the magneto is bad.

Customer: replied 2 months ago.
problem here is I don't have a meter

You will either have to get one (about $20), or you can just start changing parts.