My saga goes like this...1977 24 ft. cruiser 351W I/O OMC stringer outdrive. Replaced the motor due to a busted block. Put the boat in the water and it ran hot. Discovered I need to replace the impeller. Also had water in the oil. So I'm thinking cracked block, blown head gaskets, leaky manifolds, risers etc. Tore the top end down, had heads magnafluxed, manifolds and risers pressure tested, checked out ok. Head gasket wasn't blown, block not cracked. About all it can be ( I think ) is ingesting water through the exhaust. My question is, does anyone know if this year boat utilized flappers or any other anti-reflux device and if so, where the h*ll is it? My manual doesn't mention it at all. I've looked where the exhaust hose joins the bell housing and both ends of the risers, elbows and everywhere else I can think of. Anyone got ideas? I'd love to get this thing in the water this year...All help is much appreciated.<br />Dan
