1985 Merc 9.8 water pump problem

[HT2 LAMB]

Afternoon, helping a friend with his Merc 9.8, mid 80's, can't find serial number. Had to replace the water pump. 0.456 kit with new guide sleeve. Every time we put it back together, the plastic guide sleeve comes off and no water goes to engine. The old guide fit snug but was cracked and slightly melted. Is the copper tube supposed to seat in the upper water pump housing or does the guide sleeve act as a coupler? Also, the old guide tube fit snug in the top of the water pump housing but the new one does not. We could just use the old sleeve but it's cracked. The part number for the 9.8 water tube guide sleeve is the same through all serial numbers. I'm wondering if the tube has been cut or what else it could be. When hose is hooked to the copper tube there is good flow though the non-thermostat motor. Thanks for expertise. Go Navy!

 

[Dekker500]

I have the same engine and year (but with .438 shaft size). I opened up my water pump twice in the last two weeks, and I had the same questions, but it was easy enough to test and answer.

The guide sleeve sits in the cover assembly, and its purpose is literally to guide the copper tube down to the cover. When assembled, the copper is actually pushed into the rubber seal at the top of the cover, and once bolted together the guide serves no purpose. You can verify this yourself, since if you assemble everything correctly (verify by feel that copper tube is in guide and guide is in cover as you assemble) and seat the lower unit until it is touching the leg (no need to bolt things), then pull the lower end off again, you will notice the guide should have been pushed up the copper tube by 1/2" or so, which indicates that the copper tube has extended past the guide by that distance (nothing else could have pushed it up).

When you say "no water gets to engine" what exactly do you mean? Are you forcing water up through the screen above the propeller? That won't work since the impeller itself will stop any flow. If you mean when the engine is running... you may have a blockage. With the pump disassembled, I used a pipe cleaner to check the tube from the intake screen to the impeller. I then used compressed air-in-a-can to blow into the "tell-tale" hole, to verify the other end.

Two more possibilities: First, physically measure your drive shaft... use a caliper, and verify your engine is actually has a 0.456 shaft. Second, are you certain you installed the key correctly? If the key is missing or if it slipped out of place the impeller won't turn, and water won't pump.

 

[warlordxx]

when I just mine after I got the lower unit put back together I used my cordless drill and spun the main shaft in a bucket of water .... doing it that way you know where any troubles are if it shoots water with the drill but not when its all together then something is plunged on the top end

 

[HT2 LAMB]

That's exactly the answer I was looking for. Reassembled it making sure the copper tube fully seated and it works perfect. Thanks!