Ignition problem

First step is to test the faulty cap theory before you spend time & money looking for a replacement. Run the genny until up to temperature. When it cuts out, remove the cap across the points & try to restart. The cap is to reduce arcing at the points (producing electrical interference (crackling radios etc), and eroding the faces of the points). It should run OK without it (if the cap was the culprit).

John, good post, but he should not run it very long (assuming that it does start) as I do believe that excessive sparking may actually kill the points after a fairly short time and he may then think that its a different problem, or he may think that it is fine to run so.

Agreed! When I was a kid, I ran my BSA C15 for a while in the garage while I was fixing/tuning it after a rebuild - forgot to refit the cap on the points. Didn't go on long enough to kill the points, but my Dad gave me a right bollocking after the neighbours came round to complain that their TV reception was knackered.

Good one!!! rated it as such too.

I built myself a 27Mhz transmitter and receiver for radio control when I was about 12. (all valve!!) I quickly found that it was close enough to the VHF television, that adjusting the tuning allowed me to have some fun with the neighbors TV.....and the radio ham a few doors up always got the blame!!!!

if iremember my old engins right the cap that you are talking about is called a condencer it stores a charge of electricity and when the points break it sends a serge to the coil giving the spark you can charge the condencer by putting power to the wire with the case grounded then discharge by touching the wire to ground caution they will bite you might find one off of an old red belly ford tractor

If this problim related to temperature ,the reason must be the coil

you can troubleshoot the system by disconnecting the capacitor after worm up and restart the engine ,if no help then the insulation inside the coil is damaged causing internal leak with the raise of temperature.

Good point, but he did not mention a coil.....perhaps he should have!! Perhaps he has some type of magneto ignition?

Agreed, your problem is the coil. I have seen this one many times before.

When the coil warms up the coil winding has a bad spot in it and opens up.

find a replacement coil...

Hold on here a minute! I had this same problem with my Onan, same vintage and a 4000kw. Turn out to be the push rod seal for the breaker point was allowing oil from the crankcase to be forced up under pressure of the blowby and the oil contaminated the points casusing missfires and stopage. Let it cool off andf the oil drain back down, it would start right up.

Food for though Pull off the cover check for oil.

Dellori3

I had the same problem with a 64 Plymouth. It would quit if it had been running for over an hour. Turned out it was the coil. The windings were epoxy insulated and they became notorious for not lasting long. The heat would break them down. I put an oil coil off a Ford on it and never had another problem.

One of the checks for a bad condenser is to check the spark. A bad condenser will cause a red spark and the engine will not run. Usually if you can find a condenser that will fit, it will work. So while you may not find the right part number, you really only need to find one that has the same mounting and is the same size.

I ran a lawn mower off a six volt battery and a twelve volt coil by running wires to the points, the condenser is connected in parallel with the points.

After the engine stop pull the spark plug and grounding the side of the plug to the motor block, observe the spark or the lack thereof. If you have a red spark, then you are right the condenser is bad.

This procedure is only good for an open circuit cap.

If the cap is shorted, you will not have a spark in the first place, that was the reason for the test procedure for the previous poster.....

http://www.gmcws.org/Tech/dsimmons/onan/onan.html#motor-generator-wiring-diagram

Try this place

I believe you have a model CCK gen set. I have both a parts and service manual for this model. The original # for the condenser mounted to the points is 312-0069. NAPA lists 701312 as the replacement for it. It appears to still be available. Also point set original # 160-0002 crosses to 701035. I also had oil contamination problems on mine. I will try to cross the coil for you. I think that will be the problem.

Awesom Bob thank you the seal for pushrod is well worn although I notice little oil. I would agree from posts coil is the proublem.

Great posts everyone it's cool to learn from such a versital experence base