Jim, a blown head gasket isn't necessarily determined by water in the
oil. It could be the "rough running" is because of some fire
extinguisher stuff, got in the distributor, but I doubt it. OR the
engine was hot enough that it's causing the fuel to pre-detonate. or
even vapor lock in the intake manifold. That bad thing is that even if
the heads and gaskets are ok, the over heating can still cause the
valve seals to get brittle and eventually start leaking oil into the
valves, this is usually evident by a puff of blue smoke on initial
start up. Hope all works out for you.


JimH wrote:
wrote in message
oups.com...
Jim, tht doesn't sound good at all. I think you may have burnt valves,
a blown head gasket[s], maybe even cracked heads.


Sorry for the downtime, man. especially when your vacation is just now
starting..

Good Luck!

JimH wrote:
Cut out of work at noon and scrambled to the boat to hook up with friends
of
ours, meeting them at the mouth of the Vermilion River with boat our
boats.
We arrived first and once safely past the breakwall idled while waiting
for
them. The trip was perhaps 15 minutes tops.

I started to smell something burning and saw puffs of smoke coming out of
the engine compartment. I shut down the engine and grabbed a fire
extinguisher while my wife threw out the anchor, then opened the engine
compartment to see smoke coming off the engine and to hear hissing and
popping. Gave it a shot from the ABC dry chemical fire extinguisher
thinking there may be a fire. Saw the temperature gauge pegged at 250F.

Radioed our friends who towed us back to our marina. The marina mechanic
checked to see if there was any foaming or burnt smell with the engine
oil
(none) or oil in the bilge (none). Sigh, maybe a good sign, or at least
I
hope so.

We ended up leaving the boat with our mechanic and spent the day on our
friends boat. After 3 or so hours I got a call from the marina, telling
me
they checked out the engine (after letting it cool) and judge it to be
OK,
although the impeller needs replacing. They said I could safely move the
boat to my slip if I wanted to until repairs are made.

We got back to the marina later today and I took the boat from the gas
dock
to our slip, with the temperature rising to 220F during that short trip
from
the gas dock to our slip (5 minutes). The boat also ran very rough
during
that short trip

So.......besides replacing the impellor any other suggestions on what I
should ask the marina to do? What is causing the rough engine,
especially
after having a tune up only 4 engine hours ago? Is there some internal
damage I may have done?

Single 1997 Volvo Penta 4.3L, Chevy 190 HP.

TIA for your answers.

BTW: My vacation started this afternoon (one week of it) and this was
the
last thing I expected to have to deal with.


As Eisboch pointed out and as was confirmed by our mechanic (and a mechanic
friend of ours we saw today) it is probably not that bad if we did not see
water in the oil and as the heads are cast iron.

The impeller is being replaced on Wednesday and we will see if that does the
trick.

As a side note: I had asked the marina to change the impeller at the
beginning of the season as I did not know when the last time it was changed
(we bought the boat last summer). They said they checked it and it looked
fine. Something had to have happened between then and last Friday.