1976 9.8 water pump

[snuffy]

This is a 1976 110 9.8 mercury. Motor would not pump water. Took apart,got new pump from mercury boat dealer, old pump broke in many pce. Got new pump in and put it back together. Pumps at higher RPM but won't pump at slow or trolling speed. Anyone got a Ideal of what I need to do to fix this???

 

[The Marine Doctor]

Re: 1976 9.8 water pump

If it only pumps at high speed, I would think there is a restriction somewhere. These can be tough to locate on the smaller engines. Might be in the exhaust, might be the rubber grommet under the engine.<br /><br />TMD

 

[snuffy]

Re: 1976 9.8 water pump

Thanks, for the advice, I will look in the places you mention. Also I did notice the top of the pump housing looked like it might had been hot and looks a little warped. It seemed funning to me also that it would pump at high RPM but not a low rpm. Only a little steam at loe rpm. If you think of anything please let me know.

 

[roscoe]

Re: 1976 9.8 water pump

Sounds like you replaced only the impeller. If there is damage to the housing, you should replace it.<br /><br />Try flushing the block with a garden hose. Force water in the thermostat housing, up the water tube, and thru the exhaust.

 

[backdraft]

Re: 1976 9.8 water pump

Snuffy, I agree with the above that there are pieces of the impeller up the water tube in the block. Take off the lower unit and stick a coat hanger up to see if you can dislodge it. Another place to look is under the big cover on the side of the block. There is a waterway port that gets blocked there and cuts off the water cooling to the block. nevjb

 

[streadway]

Re: 1976 9.8 water pump

i had the same problem with a 9.8.i bought it used,someone had ran the motor out of the water.the impelar over heated causing the housing to get hot and warp.i bought a new pump from merc.it was only around $68,came with new impelar and all new seals.solved the problem.be sure and pre-lube the new impelar,and check for obstructions in the cooling systems.