On Thu, 10 Sep 2009 06:59:22 +0700, Bruce In Bangkok
wrote:

On Wed, 9 Sep 2009 12:11:27 -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

Usually white smoke in the exhaust is caused by water leaking into the
combustion chamber.

Only problems with that idea is that first of all, water doesn't do
that. Each pound of fuel burned produced abot a pound of water. Then
there is the water dumped into the exhaust elbow. Lots of piston
airplanes have used water injected into the intake manifolds to
prevent detonation. Jets have used water injection to increase the
mass flow, hence thrust. No smoke in either case. You can get wisps of
cloud that evaporate almost instantly and never make it more than a
foot from the transom, but it isn't smoke anymore than the wisps of
white at the tailpipe of any engine in the winter are smoke.

Glycol will indeed cause white exhaust smoke. My Starcraft is glycol
cooled. It had a blown head gasket when I got it. Luckily it has a
inline four, something you can work on. I will ask the previous owner
about glycol smoke.

In short, never with water, with glycol always.

Casady