Alpha one water impeller replacement

[David Hut]

Replaced my water impeller in my Alpha one lower drive unit but while installing it to the top drive I put my finger up in the hole were the drive shaft goes
and I didn't notice a seal there. I am not sure but I think there should be a seal. It just felt like a large plastic ring that the shaft goes through and into the upper
shaft. Should there be one there and what will happen if any when I put it in the water.

 

[thumpar]

Your seal is probably glued in and that is the plastic ring you are feeling. Yes there should be a seal there.

 

[stonyloam]

I think you are talking about #10 here: https://www.mercruiserparts.com/Sho...br=80&bdesc=DRIVESHAFT+HOUSING+AND+DRIVESHAFT. Quite common for that seal to fail, mine did. As I recall it is pretty easy to replace, IF you remove the driveshaft housing (upper). You can pry what is left of the old seal out and drive a new one in.

 

[ktbarrentine]

What vintage Alpha-one do you have? There are subtle differences in the vertical shaft seals between the older Alphas and the gen II alphas. In either case, though, the lower seal is a spring-insert lip-seal that needs to be there. If it is genII, it is replaced from the top (i.e., have to go into the upper housing to replace - this is a double seal (opposing) arrangement). If pre-gen-II, then you can pop the old bottom seal out from the bottom of the upper housing (typically with a screwdriver blade or seal removal tool), then drive a new one in. Got photos?

 

[thumpar]

I was thinking of the big thick seal in the bellhousing. Looks like we need more info. Do you have a serial number and maybe a pic of the area you are referring to?

 

[stonyloam]

KT I think you are correct on the Alpha I, had mine on the bench and it was pretty easy, just don't remember exactly how I did it.

 

[achris]

Flip the drive shaft housing over, flick the old seal out with a screwdriver and drop a new one in, tap it into place with a socket on the end of an couple of 12" extensions.... Takes all of 3 minutes....