2001Yamaha90 2 strok overheating problem

[Ernhrtn3]

I have a 2001 Yamaha 90 hp, 2 stroke. New water pump, new thermostat and pop off vale and spring. Runs fine up to about 3 grand then over hears above that pretty quickly, 1-2 minutes. Cools down in 3-4 minutes and goes again. I also replaced the heat sensor thinking it was weak. Still over heating and out of ideas. How and what do I tear down to get it boiled out and passages cleaned?

[Rlilleaas]

Hi, I have the exact same model/year 2001 90 hp.

Have you seen my thread? http://www.yamahaoutboardparts.com/f...r-th27375.html

Are you confident the water-pump is correctly assembled? can the housing for the impeller be cracked?

Is any water coming out where it shouldn't? Is the "control-line operational?

It could be a blocking somewhere, salt build-up possibly but I have not heard this being an issue on these - believe it is reasonable good passages..

[TownsendsFJR1300]

Make sure the water pump HOUSING (not included in the kit), is absolutely pristine.

Any overheat damage to that housing, ANY, will cause issues.

If you haven't already, replace ALL the seals(WP KIT) for the water pump. *One little o-ring seal not seated or damaged CAN cause issues*...

Can we assume the thermostat is installed correctly?

[ausnoelm]

I guess it was over heating before you changed all the parts? if so, then you will need to remove the head and any covers to clean the water passages, be careful with potential broken bolts.