Impeller/Water Pump Issue '76 Merc 110 9.8

[tgaab]

Hi All,

I had the impeller replaced on my old Merc 110 9.8hp last summer and it ran fine after that but sat over the winter. I fired it up a couple weeks ago and it wasn't pissing water. I decided to replace the impeller on my own this time. Upon inspection, the impeller looked to be in good condition, so I left it in. However, the impeller did not seem to be centered around the shaft? The picture doesn't quite do it justice but you can see the spine on the left side is compressed more than the spines on the top/right. The spine hiding behind the shaft is compressed even more (not sure why I took such a crappy picture). The motor fires up just fine but only blows hot, steamy air when it runs.

First of all, is it normal for the shaft to not be centered inside the water pump? If so, does anyone have any suggestions as to what else could be causing this issue? I've spent way too much money on this motor the last couple years and would like to try and figure this out on my own this time! The last time I ran it was in September and I had a water stream and it seemed to run very smooth. Any help would be greatly appreciated!!

Thanks,
Tyler

 

[racerone]

Re: Impeller/Water Pump Issue '76 Merc 110 9.8

The pump has to be offset in order for it to work !.----The shaft is NOT in the center of the pump.-A fairly common problem is a washer at the top of the water tube.-On severe overheat it melts and then blocks water flow to the engine.----Pulling the powerhead off is needed and that is not that hard to do.

 

[tazrig]

Re: Impeller/Water Pump Issue '76 Merc 110 9.8

Section 8 of the below manual will give you detailed instructions on how to pull off the head.

Boatinfo - 1965-1989 Mercury Service manual for 2-40 hp

 

[tgaab]

Re: Impeller/Water Pump Issue '76 Merc 110 9.8

Thanks for clearing that up lol... I did notice it looked like the tube coming out of the water pump had melted somewhat. You can kind of see it in the bottom right corner of the pic, so it must have been running pretty hot at some point. I'll have to look into pulling the powerhead off. I've got the manual, would that be in there? Also, if the washer is melted would it be as simple as just replacing it? Or is there some serious/permanent damage I could have done? Thanks so much for the response!

 

[MH Hawker]

Re: Impeller/Water Pump Issue '76 Merc 110 9.8

It may be that it is working fine and the pea stream tube is blocked, that is common. Especially after it has sat awhile.

 

[racerone]

Re: Impeller/Water Pump Issue '76 Merc 110 9.8

The factory replacement washer is a better material than the original.

 

[tgaab]

Re: Impeller/Water Pump Issue '76 Merc 110 9.8

It may be that it is working fine and the pea stream tube is blocked, that is common. Especially after it has sat awhile.

I did wonder that.. However, after running it for a minute or so, I noticed the tube that goes to the pee hole was extremely hot and the whole engine was running way too hot...

 

[oldman570]

Re: Impeller/Water Pump Issue '76 Merc 110 9.8

What dose the cup and plate that the impeller runs in look like? Are you sure that when you put the LU back on the motor, you got the copper tube to the motor back in the water pump? If the upper housing for the pump is burnt some, it is a indication that the motor has been overheated at some point. Water steam from the tell tail can be a indication that the water jacket inner divider plate could have a crack or hole in it and cause the exhaust pressure to exit into the water jacket area and go out the tell tail also. JMO
Oldman570