Water Temp problem

[cgentile]

Olkay
Boat starts to over heat and water output out the headers slows down. Impellar was changed, belts are good.
I can let it cool down then seems fine, shut it off, Everything is good again.
Heats up and water output quits again.
Engine runs and performance is great. this problem will not be 100% hit and miss bit seems to act up when you are running it at higher speeds.

Can a faulty thermostat do this.

What gives? :canada:

1994 V6 LX

[mrfixxall]

Olkay
Boat starts to over heat and water output out the headers slows down. Impellar was changed, belts are good.
I can let it cool down then seems fine, shut it off, Everything is good again.
Heats up and water output quits again.
Engine runs and performance is great. this problem will not be 100% hit and miss bit seems to act up when you are running it at higher speeds.
Can a faulty thermostat do this.
What gives? :canada:
1994 V6 LX

Did you find all the peces from the old impeller and did you get the tube lined up correctly in the outdrive? yes t-stats can stick

[cgentile]

the old impellar was perfect....and hose seems to be fine. and nothng is pinched as there can be tons of water output when underway.

c

[MOP]

What drive are you running??

[cgentile]

Drive is a alfa one

[MOP]

A couple of ideas! Intake hose liner collapsing at speed cutting off water flow, this can not be seen and the hose may appear top be just fine. Sucking air at speed, a couple of possibilities. Water transfer tube O-ring or gimble to transom shield hose. Simple test for air induction, replace the two hoses from the Tstat housing to the exhaust with clear hoses. You need to do this with the hatch off, run the boat up to speed with someone watching the flow through the clear hoses. There should be no bubble trails, any bubble trails you will have a top end overheat as the cylinder heads fill with air.