On Wed, 9 Sep 2009 12:03:58 -0700 (PDT), fzbuilder
wrote:

Hey Guys, I have an 86 Penta 350 in my Bayliner and at start up there
is no smoke, but when it gets warmed up around 170, it starts putting
out white smoke. My oil is clean and the engine runs pretty smooth
however I am getting very little to no water out the exhaust and yes I
have the outdrive with the prop off resting in a tank of water. No
leaking water into the bilge. I just replaced the impeller and am now
thinking of the water pump, but the smoke is making think there is
another problem. Any help would be appreciated. Thanks

There are a lot of possibilities but it sounds like you are getting
cooling water mixed in with the combustion process somewhe

Blown head gasket

Rusted risers or exhaust manifolds

Cracked head or block

Replacing risers and exhaust manifolds is routine maintenance - every
6 to 10 years for freshwater boats, half that for salt water. It it
hasn't been done, that is probably your problem.