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Onan ignition questions [message #322584] Wed, 23 August 2017 22:22 Go to previous message
Ken Burton is currently offline  Ken Burton   United States
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma:
Senior Member
Ok, I have been all afternoon and early evening trying to get an Onan running.

I initially had a no spark or intermittent spark problem.

This is a wasted spark (plugs in series) system.

I initially found that the secondary coil was open (infinity). I already had an order coming from Jim K. so I had him (actually Nick) add a new Onan coil to the order. While I was waiting for it to arrive, I called Blaine and asked him to meter the secondary of a used Onan coil that he had. He read 14.5K ohms.

When the new coil arrived from Jim K. I metered it and it read 40.5 K ohms. That confused me but then I thought with my bad hearing that I mis-understood 14.5 for 40.5.

So I installed it and no spark. I metered through the plug wires and coil and still saw around 40K ohms. I cleaned and gapped the points and spark plugs. I tested the plugs on an aviation plug tester. I watched the points open and close with a test light. I checked the positive side of the coil for consistent +12 volts.

Finally I went to another hangar and took a used wasted spark coil off of an Onan engine that was mounted on a John Deer. It read the same 40.5K ohms across the secondary and still no spark. I called Blaine back and he read his again. 14.5K ohms

Tonight I got home and dug out and Onan maintenance manual. It says that the secondary should should read 14K ohms.

So now I do not understand what the differences are between our NH Onans and a these two 40.5 coils I used. I also do not understand how Jim could be selling 40K genuine Onan coils and not had previous complaints. I have not talked to Jim K yet to see if there is more than one Onan coil part number. I'll probably call him tomorrow.

At this point I think I'll probably hop in the airplane tomorrow and go get the used one that Blaine has.

One thing I have not done yet is to disconnect the condenser / capacitor across the points. There is a possibility that the condenser / capacitor is leaking.

THIS IS NOT a complaint in any way against Jim K. or Applied GMC.

I am just looking for ideas. I'm open to any thoughts.

Ken B.


Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
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