| Re: [GMCnet] Onan ignition questions [message #322589 is a reply to message #322584] |
Thu, 24 August 2017 01:02   |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma:
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Senior Member |
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Ken,
Just buy one of these:
http://www.jpcycles.com/product/3000140
They come with two plug wires too boot!
Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Ken Burton
Sent: Thursday, August 24, 2017 1:22 PM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] Onan ignition questions
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.
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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