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Rich Biebel · 08-26-2014, 08:45 AM

Sean I just read a note on one fault code page that says if the fault code shutdowns alternate between 37 and 47 it is a bad ignition coil.

You have said that you get 37 and 47 fault codes I believe.

I have seen coils fail but not very often and they do fail when they get hot. Usually only one.

Another possibility is a failed wire from the coil. It is one piece and molded in. I had one machine mice chewed thru the wire. They are carbon core wires and easily damaged right at the spark plug end....

Yes I know the coils are in the bottom of the machines lower tray.....and totally inaccessible without complete disassembly......

Sean I read some more info and here is where your problem is......

The machines controller senses engine speed from the ignition coils.....it senses generator speed from the generator at what is known as the quadrature windings. That is a small winding that makes a small AC voltage in the stator. If you lose quad output....you lose main AC output.....That never happens on your machine.....If you lose a coil the machine may shut down and does not restart probably because the coil is still not firing.....just a guess but about as good as I can come up with.

Those 2 sensing circuits are what the controller uses to compare engine speed and generator frequency. It will shut the machine down if it does not sense the proper signals from both....

I'd replace both coils....

08-26-2014, 08:45 AM	#32
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,315 Likes: 25 Liked 544 Times in 213 Posts	Re: Onan 7000 Generator problems Sean I just read a note on one fault code page that says if the fault code shutdowns alternate between 37 and 47 it is a bad ignition coil. You have said that you get 37 and 47 fault codes I believe. I have seen coils fail but not very often and they do fail when they get hot. Usually only one. Another possibility is a failed wire from the coil. It is one piece and molded in. I had one machine mice chewed thru the wire. They are carbon core wires and easily damaged right at the spark plug end.... Yes I know the coils are in the bottom of the machines lower tray.....and totally inaccessible without complete disassembly...... Sean I read some more info and here is where your problem is...... The machines controller senses engine speed from the ignition coils.....it senses generator speed from the generator at what is known as the quadrature windings. That is a small winding that makes a small AC voltage in the stator. If you lose quad output....you lose main AC output.....That never happens on your machine.....If you lose a coil the machine may shut down and does not restart probably because the coil is still not firing.....just a guess but about as good as I can come up with. Those 2 sensing circuits are what the controller uses to compare engine speed and generator frequency. It will shut the machine down if it does not sense the proper signals from both.... I'd replace both coils.... __________________ Rich Biebel S/C 1479 Stock 147R Last edited by Rich Biebel; 08-26-2014 at 09:21 AM.