Onan ignition coil
- Thread starter Glen Even
- Start date
Aparently there is a coil for a Harley Davidson MC that will work at a much lower price (probably aftermarket).
Harley Davidson31614-83A
Onan (Obsolete)166-0535
Onan (See #62, Page 3)166-0772
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Look into getting the Bovee kit too if you don't want to mess with points that fail; https://www.onanelectronicignition.com/#/
Just by keeping my ear to the ground. It others trials I try to learn from.
Hi Ken, thanks for responding. I have continuity to the points. My multimeter beeps when the points close & stops when they open. I have 4.7 Ohms between the (+) & (-) poles of the coil but get nothing between spark plug wires to assess secondary circuits.
What do you suggest I check next?
Unlike a car coil, The high voltage is between the two high voltage coil wires and NOT between the coil wire, plug and ground return to the coil. So we need to see if you have continuity between the two coil wires. I am not sure what the ohm reading should be but it is in the 1000's range. Also those coil wires are resistance wires and they are sever 1000s ohms each also.
So, initially unplug the two wires from the plugs and read the resistance between them. If it is open (infinity), then remove the coil wires at the coil and take the readings again through the coil. If they are still open go to a higher range on the ohm meter and try again. If you can not get a reading on any range, then the coil is open on the secondary high voltage side and is bad. If you do get a reading then measure each removed coil wire end to end . They too should read several thousand ohms and will not be the same as each other. . The resistance varies by the length of the wire. Obviously if one reads open then that wire is bad. One coil wire open will cause both plugs to fail to fire. One bad plug can do the same thing.
Last comment and this is what confuses many people. That coil and plugs are really wired in series (a big loop) and both plugs fire at the same time. The coil secondary has no reference or circuit to engine ground. The circuit goes out one coil wire to the plug then through the plug to ground. Then through the engine ground over to the second plug. Then through that plug and back to the coil in the second high voltage coil wire.
I hope that I did not confuse you too much.
Ken B.
I went looking for a 2 cylinder wasted spark diagram on the internet. All I found was 4 and 6 cylinder wasted spark diagrams. So I stole 2 cylinders out of one and I am posting it here. A 4 or 6 cylinder one would simply have one or two additional coils like this one.
Hopefully you can see that it is very simple. In the diagram the vertical line on the right is the mounting of the plugs in the 2 cylinders so they are electrically connected together. On the left vertical line is the +12 volt input and the line going to the ground symbol would have the points in series.
Everything is in series on the secondary high voltage side of the coil with no reference to ground. The electrons that leave one end of the coil have to make it around the circuit through the wires and 2 plugs to get to the other coil input. So anything open in that loop circuit causes both plugs to fail to fire.
This is the same thing that I posted yesterday but I thought the picture might help.
Hopefully you can see that it is very simple. In the diagram the vertical line on the right is the mounting of the plugs in the 2 cylinders so they are electrically connected together. On the left vertical line is the +12 volt input and the line going to the ground symbol would have the points in series.
Everything is in series on the secondary high voltage side of the coil with no reference to ground. The electrons that leave one end of the coil have to make it around the circuit through the wires and 2 plugs to get to the other coil input. So anything open in that loop circuit causes both plugs to fail to fire.
This is the same thing that I posted yesterday but I thought the picture might help.
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It was difficult to explain verbally. So I decided to just find a picture so people could understand how really simple the thing really is. The biggest advantage is less mechanical and electrical parts (no distributor for example) and is easily computer controlled in other applications. My 89 Toronado has three of these coills for a six cylinder engine. An engine computer decides when to fire each coil and pair of plugs. .
The other problem for the undeucated is understanding the that EVERY thing in the circuit must be installed and connected to test for spark / no spark conditions.
The other problem for the undeucated is understanding the that EVERY thing in the circuit must be installed and connected to test for spark / no spark conditions.
