Another engine temperature issue

[betayv]

Boat is inboard twin mercruiser 5.7 carbureted engines, fresh coolant system both engines one engine shows temp running in the ocean 1500 rpm 165, the other engine 190-200, both engines raw sea water pumps new, both engines not thermostat, hoses been clean of debris or obstruction, the engine running hotter engine oil is clean not milky, any help what else I missing.

 

[Bondo]

fresh coolant system both engines one engine shows

Ayuh,...... Is this new freshwater systems, on older motors,..??

Have any flow tests been done on the H/E's,..??..??

 

[betayv]

Hi mr bondo boat is a 1989, not very sure how old is the fresh water system, flow test can you explain better thanks

 

[Scott Danforth]

Back flush the raw water line and the PS cooler

 

[Bt Doctur]

then use a laser to verify temps

 

[betayv]

Yes water test been done on the ps cooler and the lines, yes laser gun been used to be sure the temp is accurate.

 

[tpenfield]

Heat exchanger clogged?
Riser/elbows clogged?
Bravoitis? (Bravo outdrives right?)
Marine growth restriction in the water duct within the outdrive?

I would be thinking a restricted flow on the hot engine.

 

[betayv]

Any idea how can I check if the the heat exchanger is clogged, not outdrives this boat use direct drive transmission