1981 7.5 Mercury water pump housing question

[buddhapi]

I am replacing the impeller and seal in the upper water pump housing in a 1981 7.5 Mercury 2 cylinder motor. #7169525, which doesn't come up on most part sites, but one site led me to believe it's a Canadian serial number? Question: in the parts schematics, it shows there to be a nylon bearing (washer) below the water pump cover"TUBE' seal. (the one with the nipple on it, which helps hold it in the housing) does this nylon bushing need to be in there? what is it's purpose?when I removed the lower unit, the "tube" seal was riding up the tube, and not even in the housing. I'm thinking the last guy screwed it up? left parts out and/or not in place.
Question in a nut shell...do I need to put a nylon bearing(washer) below that tube seal? I've never seen that patent before on a motor.

 

[buddhapi]

Re: 1981 7.5 Mercury water pump housing question

anybody? I'm ready to put the lower unit back on today, and am hoping somebody knows if I need that nylon bearing/washer in there. thank's; Greg

 

[carholme]

Re: 1981 7.5 Mercury water pump housing question

That s/n comes up as:

7.5 1981 M 5524660 - 5936300 7143038 (7143083 is the starting Cdn. s/n for the year 1981)

From here:

http://www.maxrules.com/models/Merc_model_files/7p5-9p9.html

All Canadian built engines of that era are the ones with s/ns beginning with the number 7.

Your engine is a model:

1007500 MERCURY 1981 7.5

Parts Listing for s/ns 712338 and up:

http://www.crowleymarine.com/mercury-outboard/297.cfm

Thr probable reason that you found the nipple riding up the tube and not in the cover assy is that without the spacer underneath it, the nipple was eventually cut off/worn off and allowed to ride up the tube. Therefore, I would suggest that the spacer must be there to correctly position the depth of the water tube as well as preventing any wear on the nipple of the seal.

Gerry