Re: oil sludge in exhaust manifold
i don't think it's normal. though i don't know anything about yer perticular engine, but that's not the way i understand exhaust manifolds. i think they have waterjackets around them. there should be no way for oil to get into the waterjackets to be comeing out the drain hole. if by sludge ya mean sand and mud and rust and crap, that i'd think would be normal, but not a oil mix sludge,,,,how would the oil get into the cooling system? perhaps it's cracked. then i'd believe oil sludge mix would be possible....just my 2 cents. not knowing anything about yer engine...

but i do like to guess at the answer....merry christmas and welcome. stick around, if ya like boats this is where the informed people hang out....<br />i guess it would be nice to know if it's a fresh water cooled or raw water cooled too....that might be relevat info too...