the model # is 403520 i am not sure of the year, the engine seems to run great but it jerks and pops into neutral all the time it is just getting worse. is this a transimission problem? how do i fix it?
40352 would be a 1963. Sounds like you have a worn clutch dog/forward gear. If it happens at high speed, and feels like you hit a log or underwater obstruction, that's probably the problem.
