4.3 GM Marine Engin e

tvorwerk · 07-26-2011, 01:34 PM

My engine recently over heated as the water pump impeller disintegrated. I installed a new impeller, but now there is clicking sound in the engine, heard both in the engine itself and in back where the exhaust comes out. Also the engine is not running smoothly as before. Now there is a vibration that can be felt in the floor and also while holding on to the side of the boat.
Please give some suggestions as to what I should do next.
Thanks

**Midnight Tech** · 07-26-2011, 01:48 PM

How badly did it overheat - peg the gauge or just above normal?

tvorwerk · 07-26-2011, 02:18 PM

It pegged the gage....my son was driving and he said the engine started to slow down, and then he smelled smoke, so he shut it off.

Wrench97 · 07-26-2011, 02:28 PM

Pull the spark plugs and do a Compression test.

tvorwerk · 07-26-2011, 02:53 PM

I did a compression check on each cylinder...here are the results
right side of engine 25, 75, 112
left side of engine 100, 125, 60

Wrench97 · 07-26-2011, 03:02 PM

It's hurt, do you have access to a air compressor?
There is a adapter that screws into the spark plug hole, if you remove all the plugs then either loosen the rocker arms or position the piston on bottom dead center with both valves closed, screw in the adapter and put air into the cylinder that will tell you if a valve is bad, or a head gasket/cylinder head(for example if you put air in #1 and it comes out of #3 plug hole the head gasket between the 2 is blown.

Out school is to squirt oil in the cylinders and recheck the compression if it comes up considerably the rings/piston is bad, if not head gasket/valve/head is bad.

**Basementgeek** · 07-26-2011, 03:02 PM

Does not sound at all good to me.

BG