'67 sea ray /'78 chevy 305.....moisture issue

so im having a peculiar issue with moisture in my distributor...as the engine warms and i am underway it will begin to run rough...i opened the distributor cap and it was full of moisture....i wiped it out and she ran great for about 15 min and then rough again...looked and there was moisture again...wiped it out and this cycle repeats ....any ideas?....thanx in advance....dimitri

I thought about this post when you put it up yesterday. I'm shakin my head, It's that freekin humid there ? I'm freezin my Azz here.

There has to be a crack in the cap. I was thinking you could add a flat round rubber gasket, but how ?

Replace the cap.

Sorry my friend, i'm going to talk to boat doctur today pick his brain. I'll post back.

I'm back thought a few minutes more. You have the right cap ? Not sealing correctly, maybe a aftermarket chinese made one ?

I'm loath to suggest this but here goes anyway... a small bead of silly cone on the inside edge maybe ?

No crack sealing good i don;t know like i posted i'll call bt see what he says.

Blow by coming up through the distributor shaft??? Crankcase ventilation working???? Thermostat Working??? Engine operating Temperature???? Any condensation under the valve covers??

I agree, it's crankcase moisture coming up through the distributor shaft bushing and trying to vent. Check that the crankcase ventilation hoses to the flame arrester is clear and free flowing of any crankcase fumes.