Water pump or impeller

[MrBrownTrout]

I just picked up a 1997 mercury 25hp, I have not taken it out on the water yet, I did start it at home. The problem seems to be that while its idling it does not pee any water, now if I rev it up it will pee a little bit of water. The last mercury I had did not have that problem. Does anyone have any ideas????? How hard is it to change the impeller?????? I am not much of a mechanic.

 

[WillyBWright]

Re: Water pump or impeller

Those are fairly easy to change. I think you'll need a 16mm or 5/8 wrench and a 10mm wrench. The shift shaft linkage is on the port side just under the carb. There's a retainer that pivots and pulls out.<br /><br />On those, it just spits a little until the thermostat opens, then it'll gush out convincingly. Takes about 2 minutes. If you have water coming out of the prop, it's pumping.<br /><br />Whenever I get a motor I change the gearlube, replace the sparkplugs, rebuild the water pump, and pull the prop to check for fishline. Doesn't cost much and you can tell a lot about it's condition by the old parts.

 

[MrBrownTrout]

Re: Water pump or impeller

Yes there was water coming out of the prop. I did not let it run for two minutes, so the thermostat was not open then. I might have to take it up to the lake and see what happens.