1997 Mercury 15hp Water Pump Issues

lakesidefoxfarm · #1 September 28th, 2007, 06:30 PM

This motor has been sitting for approx. 3 years since it was last ran. It is a 1997 Mercury 15hp. There is no water stream coming out of the motor. I figured the impeller was bad so I replaced it. While I had it apart I checked the water lines to make sure they were not plugged. Put it all back together and it's still not working. Should I have got the complete water pump rebuild kit or is there something else I should be looking into? Thanks Gary

emckelvy · #2 September 28th, 2007, 07:05 PM

This motor has a thermostat so perhaps you should check that as well.

You could try starting the motor with the thermostat and its cover removed to see if water is pumping up to the powerhead.

If I recall you don't get a lot of water out of the telltale until the 'stat opens. If the bleed hole in the 'stat has plugged from prolonged sitting, you probably would get nothing out the telltale until the 'stat opens.

If you don't get water pumping up into the powerhead out the 'stat hole, time to pull the lower unit back off and blow air up the water supply tube (or hook the garden hose up to it) and check for flow. If you verify flow thru the powerhead, you probably have some kind of issue with the pump.

HTH..........ed

lakesidefoxfarm · #3 September 28th, 2007, 07:16 PM

I did remove the thermostat and no water came out. I also blew air up through the water port and I did feel it coming out where the thermostat is located.

bgbass.1 · #4 September 28th, 2007, 08:14 PM

did you make sure fins on pump facing clockwise when your looking at it? just a thought

lakesidefoxfarm · #5 October 3rd, 2007, 02:15 PM

Just so I understand when I look at the fins they should be facing clockwise. This creates a pushing motion versus a sweeping motion correct? One thing I did notice was when the motor was running there was water flowing out of the 2 small holes on each side of the motor just above the lower unit. That doesn't seem right to me. I also noticed that the top seal on the impeller housing was sloppy loose. Is it possible that the seals to the housing are shot which might reduce the suction needed to get the water to the block? This seems like such a simple cooling system. Why is it so hard to figure out then?