43L OMC Cobra Wont reach WOT RPM

"I have a 92 OMC Cobra 4.3L th

"I have a 92 OMC Cobra 4.3L that went through an EXTREME overheat resulting in a blown head gasket and water in at least the #1 & 3 Cylinders. Took it to a local marine shop to have the engine rebuilt. They told me the motor had been sent to an egine rebuilder who did a "complete" long block and then they reinstalled it. They charged me for "complete long" block and I was on my way. Took it to the lake to test and immediately found that it would not run out at the 4600 RMP WOT that it had nor would it reach its previous 52-55 mph. They said it was fine and just needed to be broken in. Well a season later it still will only run out at about 3900 rpm WOT and 42mph. Runs smooth and quite but no guts or power. The prop is the same and nothing else has changed. They have checked the timming, tunned it up, replced the fuel pump & coil and still does not run right.

I just did a compression test and found the following:

Cylinders
1 -120psi
3 -120psi
5 -100psi
2 -120psi
3 -120psi
6 -100psi

I am getting ready to have another shop to a leak down test but I don't know what could be the cause. Is the above compression within the normal range for this motor or is it low?

I honestly believe they did not rebuild the motor as it still has the orig spark pluggs, the block has the factory paint & freeze plugs so I think at best they did a head job and replaced the head gasket. I am concerned one or more of the cylinders are bad (low compression #'2) and or the valves are. I also wonder if the CAM was not replaced and is worn from the over heat thus resulting in the lack of RPM's. Thoughts???

Also - I believe a "complete long block" would be new EVERYTHING with the exception of the intake & carb. New rods, pistons, crank (or turned) cam etc..."

"Well you are correct about th

"Well you are correct about the amount of work that should have been done. But there are times the new parts are not used. Like if the crank was in good condition it may not have had any work done. Same with the cam. But all bearings,freeze plugs,rings,seals,pistons,etc would need replaced for a complete rebuild.

I can't say since I have not seen what you have.

My guess is that even if you find the engine was not rebuilt as you were told it was you are SOL at this point.

The one thing you said cought my eye." Took it to the lake to test and immediately found that it would not run out at the 4600 RMP WOT that it had nor would it reach its previous 52-55 mph."
Now to me this sounds as if you did not break the engine in and just jumped in the boat and dropped the hammer to see what it would do.

I could be wrong about this but it would not be good for a new engine if this is what you did.

This is about the same as taking a new car from the dealer and hitting the highway at full throttle in the first 10 minutes and holding it there for a hundred miles.

So just who is to blame if the engine didn't work correct?"