2008 Mercury 90HP four stroke overheating.

[wrd1972]

Okay, based on what I have researched, I think I need a cooling impeller. However, I want to post my symptoms to see if everything still points to the cooling impellar.

At startup and at idle.
-There is possibly a delay before the water starts to come out the pee-hole after started.
- When it is peeing, the stream is very erratic and not consistent like it used to be.
-If allowed to idle for a few minutes, the engine power is drastically reduced if you throttle up, and most of the time, I get 6 beeps.

At WOT:
-The cooling pressure gauge is erratic and averages around "10 o, o'clock", but bounces around quite a bit. Normally, its averaging around "12-1 o'clock", and remains fairly solid.
-When I throttle down, I will likely get six beeps.

I'm reluctant to think there is a cooling system clog. My lake is very clean. The engine has the original cooling impeller from 2008.

Question. Does the impeller play a role in cooling at WOT? Or, does the velocity of the water entering the cooling intake at WOT provide the bulk of the water pressure? If the impeller does play a major role at WOT, I'm now further convinced it needs a new one.

If I do need a new impeller, should I go with an OEM unit, or will a cheaper one from Amazon go the distance?

Thanks
Bill

[playcat]

I’m no mechanic… but my Honda manual says the impeller is used at all speeds for cooling.
I would go with OEM, a slip neighbor bought an impeller from Amazon, it was made in China… it was slight too tight on the shaft and would not go on. He forced it on and it split.
The Yamaha part fit perfectly.
Just my limited experience.
Welcome!

[wrd1972]

Update:
The rubber impeller was indeed broke. Funny I got 15 years out of it. Once replaced, all of the overheating issue were resolved. Thanks for the help all.
Bill