these engines run a 1" crank, and its the only 4 stroke victa that I have come accross that does....
Quite often its the O rings inside the carb that seal the top to the bottom that fail and cause lean mixture, there was a thread on it years ago but Icannot seem to find it now.
That victa base is a goodun and still looks in good nick, I personally would either track down the cause of fault in the carb or grab a replacement engine (and suitable crank boss) and bolt it onto the frame.
