Re: Fuel in oil - where to start?
I'd bet on a leaky float needle, or in an updraft carb a possibility is a leaky "O" ring or gasket around the emulsion tube. That's the pipe with holes in it that sticks up into the airstream.
If yours (which I doubt because of it's age) has an internal fuel pump the diaphram in it may be punctured. A leaky mechanical pump wouldn't wet the cylinders while sitting.
I would put a kit in the carb. Be clean and it's no biggy.
Seafarer 29 KCB