1997 MerCruiser Alpha one Gen2 impeller question

[christoner2002]

I purchased the impeller replacement kit for my 97 MerCruiser alpha one gen2. First thing I noticed was when I removed the lower unit, there was no face seal on top of the impeller pump housing. I can see the mark where one was in the past, but it wasn't there. I looked to see if it was stuck in the upper housing, but it wasn't. What would happen with that piece not there? I purchased this boat last year, and the po said his mechanic had put a impeller in the year before. When I bought the boat, we went to the mechanic, and he was a Merc certified repair shop.
I never saw any overheating through the rpm range. The impeller looked fine, but I am the type that likes to know for sure that stuff was replaced, so I figured I would change it out just for prevenative mantinence.

Question 2. In the kit, there are the gaskets, plate, impeller, face seal, seal installer, 2 large orange orings, 1 small orange oring, and 2 small yellow orings. I know the big orange orings are for the tube coupler assembly, and the small orage is for the gear lube seal, but what are the small yellow orings for?

Thank you for any help!

 

[Don S]

Re: 1997 MerCruiser Alpha one Gen2 impeller question

The face seal basiclly just keeps junk out of the pump. There is a small gap between the pump housing and the vertical shaft. Keeps sand, exhaust, sea life, etc. out.

Three of the orange oring seals go on the ujoint shaft
The two yellow gaskets are for the drain and vent screw.
The square cross sectioned oring (orange) is called a quad ring and is for the oil passage between the upper and lower gear housings.

 

[christoner2002]

Re: 1997 MerCruiser Alpha one Gen2 impeller question

Thank you for the fast reply Don! Always great having someone like you on here to help us out. I ordered a bunch of extra orings then. I bought the bellhousing gasket kit, which included the driveshaft orings, but I also ordered those not knowing they were in there. And I ordered new orings for the drain and vent screws, not knowing they were included with the impeller kit. Again, thanks for helping us all out! It is great having someone like you to help us!