highspeed overheat mercruiser 120 (1981) ???stern drive to transom plate hose???

[merc120_81]

I have a mercruiser 120 , it overheats at high speeds. outdrive MC-1.

I have done the impeller, the thermostat, tested with a clear tube from transom to engine, and replaced the riser/elbow.

verified temps with IR temp gun/probe.

Could the hose between the outdrive and the transom plate, be leaking, and only rear its head at higher RPM??

Thank you.

[Bond-o]

I have a mercruiser 120 , it overheats at high speeds. outdrive MC-1.

I have done the impeller, the thermostat, tested with a clear tube from transom to engine, and replaced the riser/elbow.

verified temps with IR temp gun/probe.

Could the hose between the outdrive and the transom plate, be leaking, and only rear its head at higher RPM??

Thank you.

Ayuh,... It's possible I suppose,... more likely it's kinkin', restrictin' the flow...

[merc120_81]

Well two years of battling this problem....FINALLY SOLVED!!!

And the winner is...

Bellows and cooling hose, changed, found 4 pieces of previous owners exploded impeller (when I changed the impeller after I bought the boat, the impeller was completely intact...) any way... pieces were found in the hose between bell housing and transom, and the metal pipe going through the transom... Thank you very much..for all the help.