Little help with ignition on Onan P224G 24HP engine

fastline

Member
I am trying to troubleshoot a no spark condition on this engine. It has the solid state ignition module and common coil with wasted spark.

I tested the module by testing the negative lead referenced to ground and it switches that to ground just like it should so I believe the module is working just fine.

I tested the resistance on the coil pack and primary spec is 2.9-3.6ohms and I have 4.5ohms. Secondary is 14.5-19.8K and I have 42K.

Personally I usually see something open up in the winding to show it is bad but this system only has two components.

I am not sure what kind of voltage I really need at the coil but I think most will fire with reduced voltage, just a little less juice. During cranking I am seeing about 9V. I know there is some loss in wiring somewhere as just when things are on but not cranking I am seeing 12.1 at the bat and 11.1 at the coil.

The voltage is rash issue with me as I just realize some jacka** decided to remove the charging coil entirely! However, I know this engine ran this way before. Has not been started in a year and sort of uncommon to see a coil just "go bad" while sitting.

helpy help?
 
I should also add the coil PN is 166-0804 which I think is supposed to have these values? If that is the case, it may be the wrong coil?

When I bought this machine, the engine ran good but seemed to bog down under hard load. It sound more like it was starving for fuel. No biggy. It has been sitting until I had time to review it. I am now wondering if this was more of an ignition issue.
 
Well, I am no expert, but my first thought when you said it worked, sat a while and now it doesn't is to ask when you test for spark, is the opposite spark plug wire hooked up to the other plug? If it is not, you will probably never see a spark where you are checking at.
That really threw me for a loop on an Onan several years ago.

We also saw one once that had the plug wire conductor burned off in the casing at the coil end and it had an intermittent no-start when hot or cut off when hot problem, I forget which.

The next thing is do you have the condenser hooked to the large post on the coil? I am thinking those need the condenser just like a points ignition. You say you tested the 'trigger' module and it worked. And the power lead (+) connects to the small post on the coil, if I remember correctly.

In my experience, If the trigger is working, condenser is hooked up, and sparkplugs and wires are good, then you probably have a bad coil. If you are worried about coil voltage, just hook jumper wires from a known good battery directly to the coil and see if it makes a difference.

The only other thing I can think of is (I am told) that sometimes the magnet on the crank that works the trigger sometimes goes dead and then the trigger doesn't work. And you said the trigger was making/breaking like it was supposed to. So that is probably o.k.
 
maybe scratch this one for now. I have it running. Seems that spark is micro! However, I have a running issue on this propane machine. I am going to start another thread to try an pin this down. Changing direction for now.
 
fastline
the 166-0804 is for the B,and N series and a few other engines
with point style ignition.
the P coils are 166-0761 early, and 166-0820 late.
for someone to install the 0804 coil they
would have to drill out one of module connectors.
the point style have 5 MM terminals.
the P series have 1 4 MM and 1 5 MM terminal.
thank you. boomer ( the used onan engine parts guy,
also NOS and new )
 

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