impeller or water pump failure?

Just purchased a 2001 25 HP Merc outboard (2cy/2stroke) online (mistake), claiming it was in mint condition and when I ran it, I see that there is no stream of water coming out of the hole. It just sprays and dribbles out a little.

How do I know if I need a water impeller, water pump or both? AND, more importantly, how do I know if it has already done damage to the motor?
Thanks,
Todd

Re: impeller or water pump failure?

rebuild or replace the waterpump, definately replace the impeller, and no you did not do any damage to your engine most likely unless you have ran it for a long enough time for it to warm up.

Re: impeller or water pump failure?

Does the exhaust plate (on the side of the motor) get more than just lukewarm? If so, that's too hot. The rest of the block will be much warmer due to thermostatic action.

Not sure on the newer 25's, but a lot of the smaller Merc's don't have a steady stream of water out the telltale, but rather an intermittant stream when the thermostat cycles.

If you think it's running too hot, might not be a bad idea to pull the lower unit off and inspect/renew the impeller. Also inspect/renew the thermostat.

Definitely good Piece-of-Mind preventive maintenance items anyway, it beats having the motor burn up sometime down the line!

HTH & let us know how it works out........ed

Re: impeller or water pump failure?

First of all compression test your engine, this will tell if any damage has occured. compressions to be at least 100 psi or more and no more than 10 psi difference between the two. Secondly remove the tell tail delivery hose from the plastic elbow in the thermostat housing. Restart the motor and run it. Check it doesn't get to hot by placing your hand on the side plate just behind the switch box. dose the water now come out o.k. It will not come out the elbow until the engine heats up a bit then a stream shoud appear. If you can not hold your hand on the side plate because it burns you hand then something is wrong..... Remove the thermostat and cover and restart again. If water dosnt flow out of the head within 10-15 seconds of running you need to check your w/pump.