Your mechanical advance weights may be gummed up or a return spring has broken.
Even if this isn't what is causing your problem, if the distributor hasn't been disassembled in its lifetime, it wouldn't be a bad idea to take the distributor apart and clean it up.

Last edited by 52Carl; 12/10/2024 2:10 AM.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission