Btw, if you have a 4.3, v6 it is not a 350. A 350 is a v8 and is a
5.7. The v6 is very similar to the v8 except it is two less cylinders.
Two banks of 3 instead of two banks of 4. A lot of the bolt patterns
on the front and back of both are identical. Thus they are somewhat
interchangable. The v6 makes an excellent marine engine as it is
lighter than the v8s but still produces a respectable horse power. And
it is just as sturdy as the v8s which are known for their ability to
tolerate some abuse and neglect.

jamesgangnc wrote:
I would consider clogged risers and/or manifolds as a definate
possibility. 97 makes them 9 years old. A rule of thumb is 5 years in
salt and 10 years in fresh but mileage can vary as they way. They all
rust and as they get older the rust and scale started to flake off in
chunks. The chunks clog them. The worst area is the risers because
the water and hot exhaust get mixed there. Sometimes you can clean the
manifolds and replace the risers. I would also check the circulation
pump and the thermostat. It would be easier if the boat is out of
water on muffs cause then you can see the water coming out or not.
That engine is a fairly solid one and should be able to survive some
overheating. Even if it was damaged it is more likely to be repairable
with new head gaskets and possibly resurfacing the heads.


Jim wrote:
"Harry Krause" wrote in message
. ..
Jim wrote:
"Harry Krause" wrote in message
. ..
JimH wrote:
1997 43.L Chevy 350 6 cylinder. Freshwater. Manifolds and risers are
original.

Tuned up just weeks ago with only 4.2 hours on the engine following the
tune-up.

Thermostat was replaced in spring.


I wonder if your tune-up guys pooched something and didn't tell you.
Not likely. More likely a scenario like this: Plastic bag gets sucked up
against water intake. Water is restricted or cut off completely. Engine
overheats and water pump fries. Engine shuts down or is shut down and
plastic bag slips away. After inspecting the water pump, mechanic
suggests that the owner ran the engine without water. Owner suggests to
mechanic that he should have seen that the water pump was on it's last
legs when he inspected it. (Write your own ending to this story)
Jim


Well, I keep reading about "impeller failure," but I dunno about that. Jim
boats on a freshwater lake. Bags, yes, but sand, sandbars, and the usual
crud one finds in coastal waters? Probably not.

Could have been a loose belt; but Jim would have found that.
Could have been a plugged manifold or riser but overheating would not have
been sudden. Also manifolds and risers run in fresh water tend to last a lot
longer.

What do you think might have been pooched and cause a failure 4 hobbs hours
later?
Jim