Yanmar 3QM30H (fresh water) white smoke.

[Compass790]

Good job talking OP thru it Wottie,
Nice job cleaning it up Rmccormi, lucky you got to it before you blew the head gasket. I get a few raw water cooled Yanmar ( salt water berths) owners coming to me for head gaskets from blocked cooling galleries as they havent been flushed. If you are in Sacramento I guess u r mostly in fresh water tho which helps. Rusted out exhaust elbows also kill a lot of the YS series yanmars that i deal with too. I built my own ss mixing elbow as didnt like the Yanmar design or price.

[Wotname]

Originally Posted by Rmccormi

Finally got down to the boat, flushed the engine, installed the manifold, new water hoses, and exhaust hose. Started the engine and it seams to be very happy! Again thanks for your support [emoji41]...................

Glad it worked out OK. IMHO, the QM series are great engines even if a bit heavy.