25 HP waterpump idle out put

[occunknown]

I have a 97 25 hp outboard SN 06550751 that has a dribble out put until hot water then a full flow till cool then back to the dribble at idle. When in the water and under full load has great out put. All hoses and output seems clear, any advice on this?

 

[matt427]

Re: 25 HP waterpump idle out put

Time to change the impeller. It don't pee til the thermostat opens. If after changing the impeller and the water is really hot, change the thermostat.

 

[joed]

Re: 25 HP waterpump idle out put

It could just be the thermostat opening and closing. My 94 9.9 does the same thing.
How long has the impeller been in the unit? I changed mine after 13 years and it was still fine, but since I had a new one I put it in and saved the old one as an emergency spare.

 

[Laddies]

Re: 25 HP waterpump idle out put

Some thermostats the notch is covered by the gasket, as long as you have good flow when the stat opens and if you want a better idle flow take the thermostat out and drill a couple of 1/16 holes in the plate to increace the telltale water flow, remember over 90% of the cooling water goes down the inside of the driveshaft housing to cool it.

 

[occunknown]

Re: 25 HP waterpump idle out put

Thanks for the replies, I appreciate the help. I removed the T stat and had good flow. So I think I will try the by pass holes and see if that makes me feel more comfortable and not feel like there is an overhear potential.Thanks again...