My 1950 3100 did same thing...very small crap passing into carburetor from tank. I put an in line filter on it . I cut the rubber hose at bottom of tank to hard line. (Note I already had the AC glass filter at fuel pump) Does not filter FINE particles. Problem SOLVED instantly. Also amazing the tiny debris in the in line filter you can see from your tank. See pictures. The picture with Debris is only driving it a few days!
Last edited by Shaffer's1950; Sat Apr 18 2020 04:24 PM.
I had a similar experience with my 38's 216. I also had some backfiring. It would start to die and then rally, buck and surge and backfire. It turned out to be the condenser. I hooked up my timing light and pointed it into the windshield in the garage. Every time it started to fail I could see the spark failng too.
I have been converting my fleet of ADs with the later sending units which have the fuel pickup as a part of it. They bolt right in and the fuel is picked up just above the bottom of the tank and has sock on the end of the pickup tube. This prevents blockage from debris sloshing around the bottom of the tank from clogging the fuel outlet. The on again/off again blockage from debris with the original setup makes troubleshooting a nightmare. Carl
What Carl and Shaffer said. I put a newer sending and pick up unit in as well. It takes a little plumbing with some steel brake line but is a major step up from the old arrangement. I eventually had the tank cleaned, the new unit and a filter prior to the fuel pump and one at the carb. Probably overkill but it keeps the junk out of the carb.
Glad that you got it going. Hope that coil really was the issue but I'm curious why a failing coil (poor or no spark) would be helped by running with choke, albeit badly. Bet that coil cooled enough or bounced enough to give enough fire to a richer mixture. ...or one thing had nothing to do with the other. What is the old saying....if you think it's fuel related....it's usually electrical and vice versa. Good to hear yours worked out pretty straightforward.