Need help with 1989 4HP Mercury waterpump

[hifisher]

I recently had overheating problems with my 1989 4 HP Merc as it quit pumping water. I just replaced the water pump impeller (that had no fins left) and now it's still not pumping water to the head. I'm very certain I matched the watertube. What else is clogged, plugged, or needs replacement? Thanks.

 

[Laddies]

Re: Need help with 1989 4HP Mercury waterpump

if you did not get the old imp. blades out of thr system they are probably blocking the water passage usally under the exhaust water cover

 

[hifisher]

Re: Need help with 1989 4HP Mercury waterpump

 

[hifisher]

Re: Need help with 1989 4HP Mercury waterpump

I had removed some blade bits behind the intake screen before installing the new impeller. Taking your advice, i found no more rubber but put air pressure up the water tube and it's passing air. What's next?

 

[Laddies]

Re: Need help with 1989 4HP Mercury waterpump

with the lower unit off the engine and the prop off the unit (for safety sake) turn the drive shaft with an electric drill and see if it will pump water out of a water tank to tell if it's pumping,if it pumps raise the unit in the water till the pick up is almost out of the water to ck. for vacume leaks (many times the rubber grommets leak and need to be sealed. if it pump then your problem is up top ---bob

 

[hifisher]

Re: Need help with 1989 4HP Mercury waterpump

Laddiesservice - liked your drill method. That showed me the pump was working. I put it back together again, went out duck hunting and she ran cool. FYI, the restricter tube melted somewhat in the initial overheat two weeks ago, and now it doesn't drip water. I hope that's ok?? Thanks -Jack