engine getting hot

[tjjarrell]

after getting boat de-winterized, the mechanic says the engine is gettin hot while idling.  waterpump is working when the exhaust manifold system is not hooked up, but when hooked up properly the waterpump is not pushing water efficiently through the system.

[lilfoo2225]

huh? 

[bullet1w]

What did the mechanic suggest for a fix?  Did he have any ideas?

[masonlk]

Take a look at your impeller. If it's starting to deteriorate it won't be efficient at idle.

[wakejunky]

take the impeller OUT of the pump and look at it. if the vanes even slightly curl over replace it. i ruined an entire weekend think my impeller was good just because it wasnt cracked or missing vanes. i change it every year now. and i always carry a spare.

[lilfoo2225]

check/clean that strainer too!

[smars]

Check your exhaust hoses that run off the manifolds down to the mufflers. I had a problem with reduced flow and heating up at idle, finally narrowed it down to the fact that my exhaust hoses had completely come apart and caused a lot of back pressure in the cooling system. Just pull both sides and take a look with a flash light.

[tjjarrell]

New impellar did the trick, thanks.