M38A1 started to run very rough with misfires

[Blaise]

When I acquired my M38A1 I had to replace the blinded 24v spark plug cables as it was running on 3ish cylinders.
It then run well for approx 50 mi and started to run rough. Replaced the condensator and it run well for approx 100mi.
Then suddenly started again to run very bad. Almost no power, misfires and coughing.
Points have been set to 0.02", the gap was too big.
Running better but still bad.
My mechanic set the Dwell at 40 instead of 42...
I have massive rust pieces in the gas tank.
Next is to replace again the condensator and replace the igintion coil as well.
Do I have a tension issue that damages condensators one after the one?
Should I check for air leaks in the carb?
Thanks

[bmorgil]

I am of the belief that a bad condenser does occur but, it is rare. I have yet to see one that doesn't have some physical sign of being bad, be bad. I have put a few across an oscilloscope and never found one that looked good but was bad on the scope. That being said, they do go bad. Several in a row is not likely. The condenser provides a path for the voltage spike to ground when the points open. If the condenser goes bad, when the points "break" the arc from the sudden break in current for lack of a better term, burns the points up quickly and does not provide a good clean discharge from the coil. When the points open the coil must discharge via the coil high tension terminal. If the condenser is bad the points will arc and burn and the engine will run rough if at all. The dwell is a direct result of the point gap. Dwell is the amount of time the points are closed charging the coil. 42 vs. 40 is about .0005" of an inch. of point gap. It seems like every time you mess around with the points it runs OK for a while. I would start with cap, points, condenser, rotor and plugs since you replaced the wires already. The coil should be checked with an Ohm Meter. I don't know the values for the 24 volt system but, they are in the tech section of this forum, or one of the guy's might know. I would inspect the primary wiring to the coil and be sure you have the correct voltage at the positive of the coil. A bad connection or ignition switch could also be the cause if this is an ignition problem.

The massive rust pieces in the tank points to possible fuel problems. The Carter carb does not tolerate contamination well at all. I would immediately get a filter in the line AFTER the fuel pump and before the carb ASAP if you don't already have one. If the ignition checks out you may want to go through the carb and replace the tank.

[Blaise]

This is excellent directions.
Cap and points are new.
True that when the condenser went bad, the points were fired, with a big hole through the contacts.
Thanks for the comment on the Dwell deviation.
I will check voltage at the coil and get a gas filter.
I agree that it shouldn't be something too serious .... hopefully.
I was thinking of checking pressure at each cylinders as well