Re: Leaking crankcase leads to overheat condition?

[Don]

Well, I too am not terribly confident in the crankcase leak theory. But, running lean surely does increase combustion temperatures, so your diagnosis can not be ruled out. Are you sure the water pump is in good shape? Those impeller housings only have three retaining screws, and not much "meat" to seal the SS impeller plate.
In any event, I would consider richening up the high speed jet by .002" to ensure a good mixture for today’s fuels. Your weedless prop may be over revving the engine, which may lead to trouble also.