water pump replacement questions

[DoGood]

This is for a 3.0L mercruiser, alpha 1 gen 1. I am replacing my water pump while I'm replacing the bellows.

The kit I got from Sierra came with what seems like 3 extra o-rings, I cannot figure out where they go. They are not the one for the water pump base, though similar in size, and not for the vertical drive shaft. Am I correct to assume they are for another drive? The kit also came with 2 extra gaskets that are similar to the ones that go between the housings and metal gasket. Am I correct to assume these are for a different application?

Also, when installing the lower unit to the upper unit case, the shift shaft (on the upper housing) doesn't seem to go down enough to allow the bell housing to be installed. It will turn such that the lower unit will shift, but I don't think the bell housing will be able to be installed on it. Is there a simple step I'm missing? How much vertical play should be in this shift shaft? I have none when I bolt the upper unit to the lower unit.

Any help would be greatly appreciated. Please let me know if you need any additional information in order to help with my problem.

Thanks

 

[Brentathon]

Re: water pump replacement questions

FYI: ***Do a search on a recent post of mine. I just spent 10+ hours and over $460 to finally figure out, that my Sierra brand impeller had a material defect. It was new, and it only was pumping approx 70% of the water that I needed, to keep the engine cool at higher rpm's. It was not something I suspected, as the flow was strong when I pulled the hose coming from the drive, and I knew I never ran it dry or hit bottom, or anything.
I am waiting to hear back from my warranty claim.

 

[DoGood]

Re: water pump replacement questions

Thanks for the tip brentsalamone. If I ever get this thing back together and I have cooling problems I'll replace the impeller first. I don't think your thread you are referring to says anything about the impeller being the problem, you should update it for future reference.

Since you just did this job, do you have any insight on my issues?

 

[bigskiohio]

Re: water pump replacement questions

mine had extra too and the sierra pump worked great. the base pump was the hardest to figure ot bot really only two were close one was slightly big and the other one was a little tight which is th one i used and the gaskets were self explanitory as which ones to use as mine had alignment pins .in the base fill the area between seals with grease and lube the oring before installing. use non hardening sealer on gaskets i used some the merc dealer gave me but others say you can use aviation gasket sealer at napa.

 

[cr2k]

Re: water pump replacement questions

Did you have the drive in forward gear? This is an absolute must when working on a Mercruiser. Very first step. That said you need to turn your shift shaft in the lower CCW all the way and make sure it is full in forward gear by a little ccw pressure on the prop. Now your shift foot should be pointing straight forward as is the shift fork in the upper. When you get close to all the way in you can turn the prop slightly ccw to align the drive shaft splines. Making sure you captured the water tube.

Also there is a SS washer that goes on top of the shift shaft under the foot. If this is not there you will not be able to engage the shift fork.

Replace the lower with the drive about 1/2 way up. This will ensure that the lower stays in F.