overheating question

1985 Mercruiser 5.7 liter, alpha 1.

The engine runs great, and runs right at 140 degrees, and if I'm running at cruising speed, bring it off a plane, and idle for a bit, the engine stays cool when I turn it off. But, and here is my question.. if I'm runing at cruising speed, bring if off a plane, and turn it off quickly, then the engine heats up to like 200 degrees.

Is this normal? I'm sure the proper way to operate the boat is to not turn it off abruptly when coming down from cruising speed, but if for some reason I do, it heats up.

(On a side note, when it is up to a higher temperature, the starter doesn't turn the engine over very fast, I'm guessing that is normal because things would maybe bind up a bit or the starter just doesn't like to be that warm)

Thank you for any responses.

Re: overheating question

if I'm runing at cruising speed, bring if off a plane, and turn it off quickly, then the engine heats up to like 200 degrees.

Is this normal?

Click to expand...

Sure it's normal, you need to slow it down to idle or low speed and allow it to cool off a little bit and dissipate some of the heat built up from the run.

Might want to check your timing, 200? shouldn't effect the engine, but in the enclosed engine compartment it can cause vapor lock with the fuel system.

Re: overheating question

Thank you Don. My engine compartment is pretty closed in, I will check that out. Will also check the timing.