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echoffmann

520H Ignition Coil readings

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echoffmann

I'm having trouble getting my 1990 520H going after 3 good years, the Onan P220. Last mowing going up hill it started to sputter, lost power and died. Towed it back to the shop and got it running, idled fine still sputtered at high RPM, got to my spot and engaged the PTO and it killed. Replaced fuel pump and went to try it....no start. Looked like weak spark on the front cylinder and no spark for the rear.

 

I found the specs for testing the coil and the primary is fine at 3.5ohm. When I go to test the secondary I get a reading of 21,670. The book says the high limit is 19,800, I'm wondering if this is enough to cause a bad coil and my problem or if I should be looking elsewhere? Coil is the 166-0820

 

Used a test light on the leads from the ignition module out of the stator and the light surged so I think that means that is alright.

Edited by echoffmann

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N3PUY

I have a good coil here in my hand and the primary is 3.9 ohms and the secondary is 21,100 ohms.  Higher than the limit but ran good.

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echoffmann
1 hour ago, N3PUY said:

I have a good coil here in my hand and the primary is 3.9 ohms and the secondary is 21,100 ohms.  Higher than the limit but ran good.

Thanks for the input! I found a post about adding 12v to the + side of the coil then cranking to test and that worked, I have spark when coil is powered by an external source. So, the coil seems fine, now I guess off comes the shroud and start following wires.

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N3PUY

I don't think the shroud needs removed.   The wire that powers the coil is in the harness between the motor and chassis.  Look at the 9-pin harness connector.   Take it apart, clean it , bend the female terminals to tighten their connection.   That might be it.  Many posts about that connector.   

IMG_0692 (800x600).jpg

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N3PUY

When you ran the wire from the battery to the coil you bypassed the ignition switch and the seat switch and the PTO switch.  

  Problem could be any of those but I think connector first and ignition switch second.

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echoffmann
7 hours ago, N3PUY said:

When you ran the wire from the battery to the coil you bypassed the ignition switch and the seat switch and the PTO switch.  

  Problem could be any of those but I think connector first and ignition switch second.

N3PUY you nailed it!!! I happened to have a test light on the coil when I bumped a wire and the light came on! Narrowed it down to a broken spade on the PTO switch on the PTO not making a solid connection. All other Ignition components checked out fine so I was getting baffled.

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N3PUY

Don't you wonder how a terminal just decides to break!   Happened to me last week.   310-8 wouldn't crank, just click.  The terminal on the cable from the solenoid to starter broke off. Just no good reason for that.

I'm glad you got it fixed.

Have a happy day,

Joe

 

 

 

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