Ignition or carburetion?

[Mogul]

Working on a 33 Flathead 4 cyl. The engine initially will start and run fine. However once it warms up, it seems to develop either a carburetion or ignition issue, where it won't do anything but idle. If you give any throttle, it falls flat on it's face and back fires.

The truck is still 6V(pos grnd), has a newer coil and likely condensor. We have taken apart the carb and cleaned it thoroughly so to try and rule a carburetion issue out.

Any thots on how to track down the problem. The points appear fine, no green build up. We have attempted to adjust them, but this has not made any difference in how the engine runs, once warmed up?...

As the engine runs fine from a cold start, then once warm it develops this rough running condition, it seems obvious that something is out of adjustment or becomes faulty(iginition?)...but we are out of ideas...

[56f600]

I've got an Oliver oc-3 that has done the same thing. We found that the magneto would warm up and cause the thing to die. Try replacing the condensor, that solved the problem for us. Remember 90% of all carburation problems are electrical.

[Mogul]

As suggested, we replaced the condensor, and our problems, disappeared...thanks for the suggestions.

[41Clay]

How well did you clean the carburator? It sounds like my vehicles when they're not getting enough fuel into the cylinders.

After I dipped my carb parts in cleaner I decided to see where all the little holes flowed to and in the process discovered that the dip did not clean all the holes enough, mainly the needles (or whatever they're callled). So using a tooth pick and my mou...err.. some air and water, I got all the the grunge out of them. So you may want to take out your jets and check to make sure that the fuel can flow through them. it's been along time, but I beleive the needles were screwed into the top of the jets, in fact they may be the jets but I don't know much about carbs.

Good luck!