Onan Gen Set no spark

[Ed Kennell 37,911]

Trying to get my 1950s vintage Onan gen set running.      It ran when I parked it in 2018.

M/N 205AJ  3RV/1H        S/N 53C723082

ONAN, a division of Studebaker Corp.

 

Has compression and fuel.    Spark is too weak to fire the plug.          I have pulled the flywheel and cleaned the magnets....no change.     

 

   I could use some help to check condenser, coil, points.    How to check and set the magnet gap?

[squonk 40,949]

First thing I would do is clean the points. dirty points won't break cleanly resulting in a weak spark.

[c-series don 8,644]

Ed is that a two cylinder? If so I may have the manuals for it? 

[Ed Kennell 37,911]

3 minutes ago, c-series don said:

Ed is that a two cylinder? If so I may have the manuals for it? 

No, it's a single Don.   But thanks for the offer.   Probably a 10 or 12HP.       I have not been able to find a manual for this model.     I did find Studebaker owned Onan in the 1960s.

I'll post a couple pics today.       I just don't have much experience with these under the flywheel ignitions.

[Ed Kennell 37,911]

[lynnmor 7,294]

Here is the manual.  Point gap is .021", plug is .025".  I took a quick look thru the manual and didn't see information on the magnet gap, perhaps it is a fixed distance, typical clearance is .008" to .012".  Use a points file, or other thin fine file to clean them, abrasives can leave grit embedded and cause poor contact.  Also, I didn't see the ohm readings expected for the coil or condenser, I would just use readings and testing from popular engines and they should be close enough.  Usually you can do a quick test to a condenser by putting an analog ohmmeter across it and quickly reversing the leads, a quick blip of the needle is a good thing.  You should have a good attraction from the ends of the magnets to a flat screwdriver, in the good old days magnets could be recharged (remember an auto electric shop on Market Street near the bridge)?

[Handy Don 12,050]

On 8/6/2023 at 9:04 AM, Ed Kennell said:

Thanks for posting this image showing the magnet bar attached by rivets and the drilled-out spots on the counter weight that balance the flywheel. Thinking of the manufacture, it wouldn’t surprise me to find that the drill for balancing was part of the balancing machine so there wouldn’t be any time wasted for mounting/dismounting.

With just the two magnets, it seems this is a magneto engine, right? So electric start would come from battery charged by the attached generator?

Edited August 9, 2023 by Handy Don

[Ed Kennell 37,911]

1 hour ago, Handy Don said:

With just the two magnets, it seems this is a magneto engine, right? So electric start would come from battery charged by the attached generator?

Exactly Don.     

[Ed Kennell 37,911]

OK, it seems the coil is dead.   Dead short from primary to ground.

 

Not much hope to find a good 60 yo coil at a reasonable price.    This may become a Wheel Horse powered Gen Set.    

 

[Handy Don 12,050]

24 minutes ago, Ed Kennell said:

This may become a Wheel Horse powered Gen Set. 

Challenge when separating a motor/generator is that often the generator shaft has only one bearing. The other end is often a tapered socket that fits over, and aligns with, the tapered crankshaft of the motor. 

I suspect finding a coil might not be that onerous (price may be, however!) and failing that, a replacement engine from another generator?

[Ed Kennell 37,911]

42 minutes ago, Handy Don said:

generator shaft has only one bearing.

Yep, I would leave the engine attached.  Just need to find a pulley near the correct OD with a tapered bore to put on the crank.  Just leave the plug out for zero compression.

Or tear it down and remove the piston, rod, and valves.