Searay Sundeck 240 Overheat issue

[sessasells]

Last July of 2013, had the Seapump kit replaced, thermostat and tune-up. Went to take boat out last weekend and it overheated within 10 minutes, not even time to open it up. When towed back to dock, hooked water supply to flush outlet at stern of boat and it cooled down to 70' in seconds and would not overheat at idle. Turned water off and it overheated within 30 seconds. Does the flush outlet bypass the thermostat or are there more serious problems. The engine is a mercruiser 5.0L Serial OW344212. It does not have a heat exchange and water appears to exit the foot area whether hooked to hose or pulling water from the foot of stern drive. Any suggestions?

 

[Bt Doctur]

Re: Searay Sundeck 240 Overheat issue

Describe this flush outlet at the rear of the boat. sounds like someone ran the motor with no water attached to the drive and smoked the impeller.
What type of drive? If Alpha GEN II you need to use muffs to run it.

 

[Bt Doctur]

Re: Searay Sundeck 240 Overheat issue

Mercury, Mercruiser, Force, etc. - Closed Cooling System (BRAVO) - 5.0L,350 MAG,MX 6.2L MPI STERNDRIVE
Enlarge the pic to see if 2 or 42 is the flush adaptor

 

[bspeth]

Re: Searay Sundeck 240 Overheat issue

smoked impeller

 

[cr2k]

Re: Searay Sundeck 240 Overheat issue

A boat will usually run cooler on a hose because you are forcing water to it so it doesn't have draw the water via the impeller.