Onan Engine

[BSeyler]

I have an old (probably early 70's) Miller welder with an Onan Model CCKA-MS/2748J engine. It quit running last summer and I just didn't get a chance to work on it until now. It does not have spark at the plugs. I verified that by pulling a plug, grounding it on the head, and cranking. It has power on the primary side of the coil, so I was wanting to check the points next. I assumed they were located under the flywheel. I have the flywheel off but it looks like the whole front of the case, including the seal would come off, and I can't see any wire there, either. The positive side of the primary from the coil goes behind the manifold to a little box. I'm not sure if it's a magneto, or what I'm up against here. Anyone have any experience with this particular engine? I've looked for a manual, but can't find anything left in print.



Thanks!

 

[B.G. Smith]

The points are in that little box under the manifold. While you are in there, remove the points and pull the little pushrod out that opens them and make sure it is clean and not sticking in the bore. Lube it with some light oil. bg

 

[BSeyler]

bg,

Thanks for the quick reply! I'll tear into that in a jiffy. It's a pretty good old welder and doesn't get used much, but is really handy at times. I shudder to think what it would cost to upgrade.

Bud

 

[DJW]

BSeyler, if I have trouble finding any instructions etc, regarding machinery, engines etc. I use a local library, it's surprising how much stuff they have, also one can make a copy if too difficult to remember solution, plus check parts incase one has dropped or missed, as in general there's plenty of illustrations and drawings to take to a parts dealer, have saved me countless hours over the years.

 

[Hoefler]

They are in the little box for sure. If the engine has many hours on it at all, oil can and will migrate up the shaft that operates the points. Excessive crank case pressure can cause this in older motors. Make sure the crank case breather is clear, it either goes to the carburetor or the atmosphere. Clean the points with carburetor cleaner and set them to . 020, also you might consider changing the condenser as well.

 

[BSeyler]

Thanks for all the help - I have it running again. Turns out it was a switch on the welder panel. When using it as a generator, you set the throttle to fast idle and the switch to power. Switch to weld position and full throttle to weld. If the switch gets set to power position under full throttle, it kills the engine. Switch was bad and wouldn't let it run under any condition. Isolated it and away it went. A new switch should have me back in business. I also think I have a lead on a manual for the engine. I have the original for the welder, but it doesn't have an engine section.

This design was all new to me. I worked on a lot of smaller engines in high school with my job at an implement dealership. (Also took the Briggs & Stratton from my dad's lawn mower apart and put it back together once when he was at work. Sweated that one a little trying to figure out where all the bolts went before he got home!) They were mostly Wisconsin, which was New Holland's choice at the time, with some Ford six cylinders, also. As I remember, all the Wisconsin engines had distributors, but that's reaching back a few years. Anyway, thanks for the help!
Bud

 

[agrainger88]

G,day Bud, I'm pretty sure I have the same problem as you with the onan/miller welder. How did you isolate the weld/power switch to get the motor to start?Hope you can help me out.

Ash.

 

[BSeyler]

Ash,

Boy, you dug up an old thread! I was trying to remember what I had done and had to go look at it, again.

There are actually two switches. One is beside the throttle on the cowling. It is closed at the idle and power settings for the throttle. When the throttle is opened to weld speed, the switch is open. If the switch on the panel is not set to weld, it kills the engine. I put a jumper wire on each switch to isolate it. (Maybe bypass would describe it better. ) What you want is a closed circuit all the way through in order for it run, but you do not want it to supply more that 120V AC. That is why the engine won't run at a higher speed when set on power. By using some aerosol electrical cleaner, I was able to get the switch on the panel limbered up and it was the culprit.

How long has it been since your welder was running? I would verify that the switch on the panel is in the weld position if you have the throttle open. I flooded mine once and cranked it a while with the throttle wide open. It then hit me to change the switch on the panel to weld. Cranked it again and it finally took off.

If everything with the switches checks out, you may need to check for power at the points, etc. Hope this helps you get it going. They sure are a handy little welder. We use ours occasionally for repairs at the barn and corrals. Mine also got a workout a couple of months ago when the power was out for 17 hours. I had two refrigerators and a freezer plugged in.

Bud