Re: Guess it might not be the points.... Suggestions!?

Posted by BH On 2012/8/20 9:40:53

Steve -

You may have a situation that seems like one big problem, but there are actually several underlying issues. You have to keep working to eliminate each possible culprit - one at a time.

WRT backfiring, please do verify the timing of the distributor to the engine, which can be done without engine running - as described above. Then, make sure that the #1 plug wire is, now, at the correct position on the cap; of course, if you got the firing order right, the rest of the plug wires should follow naturally. If everything else was OK, that would be enough to keep an engine running at idle, without backfiring or stalling.

WRT weak spark, one thing I haven't heard you report on is the condition of the condenser (capacitor). The voltage needed to make a spark is created, when the points open, by the collapse of a magnetic field that had built-up in the coil when the points wee closed (and all happens very quickly). However, the condition of condenser, which serves as a buffer to prevent premature failure of the points, may have some effect on spark. Have you inspected the lead coming out of the condenser to make sure the insulation is intact? Have you tested the capacitor to see that it is not leaking, electrically? This test can be done with a VOM or DVM.

Also, have you inspected the condition of the breaker ground lead - that is, the primary wire from the coil to the distributor? That lead connects to a post/terminal on the distributor that passes through the housing, but must be insulated from the housing. Be sure to inspect the condition of that bushing/insulator, as well.

Then, it's possible that the starting system is adding to your woes.

The carburetor starter switch first appeared on the new Clipper, which was a mid-year entry to the 19th Series (1941) line-up; proper operation, along with a few precautions, was described in Service Letter Vol. 15, No. 11 (June 1, 1941). That system was subsequently adopted across all models of the 20th Series (1942) and used up through the 26th Series (1953). Yet, troubleshooting must have been a bit difficult for even dealership technicians to follow, as checks and adjustments of the carburetor switch were covered in SL Vol. 17, No. 1 (January 1, 1943).

Except for a change to this system for 1942 that was later rescinded, the factory set-up works as intended - provided every link in that chain is in good working order. Seems to me that the biggest problem has been band-aid solutions that were applied in the years since the factory-trained dealer network evaporated - rather than getting to the root of the problem and fixing it correctly. Adding a dashboard switch is not uncommom.

Gotta wonder, then, if that dash switch was added because of a malfunctioning carb switch, which depends on vacuum to operate properly, but the vacuum problem has only gotten worse since.