JD G is missing

[John Athey]

She runs great at idle, but once I open her up, she misses. The carb has been rebuilt and I adjusted it. Points are new. What should I do? How can I tell why / how she is missing?

 

[cogger]

My guess is it is in the carb. Possibly the load needle needs to be opened a little more.

 

[Peyton]

Before you spend anything on the carb or mag, get new plugs. Good ones. A friend just had the same problem. Ran perfectly at idle, ran lousy under a load. He rebuilt the carb twice, cleaned out all passages, changed the float, checked the jet, rebuilt the magneto, adjusted the valves, checked for cracked rings, and removed the governor to check for problems. He adjusted the timing multiple times. He had checked the plugs - they had a good, bright white spark. After all that, he fired it up and it ran lousy under load. Changed the plugs, runs like a champ. I don"t understand how load/compression can effect a spark plug, but it can. Change the plugs and you may avoid a lot of time and expense. Good luck.

 

[Gifford Knapp]

Yes compression changes ability of plugs to fire. 50 plus years ago when an implement dealer we had a plug tester. You added air pressure to it untill the plug quit firing so we could save only the good ones. Wished I still had it. Gifford

 

[Anonymous-0]

I had a G puller that did this under load and it was the condensor when it had points,JD B years ago too.

 

[John Athey]

So which one is the load needle?