Alpha 1 Gen 2 Shaft seal question

[Paxdad]

Over the weekend I removed and replaced the impeller in my 2006 Alpha 1 Gen 2 lower unit. When I dropped the lower unit I noticed that the shaft seal was missing (shaft seal is the seal that goes down over the shaft on top of the water pump housing. I also verified that the missing seal was not stuck up in the upper housing.

The rebuild kit contained the new shaft seal and install ring/ toool and was specified in the installation diagram. I replaced eveything accordingly. Can someone tell me what the purpose of the shaft seal does and if was not installed what type of indications I might experience?

Once everthing was reassembled, lube added, I hooked it up to water hose/ ears and ran accordingly checking for shifting etc. All was good.

I then proceeded to the lake and ran the boat all goood but operating temp was around 180 degrees which seems higher than with the old impeller. The motor is a 2006 5.0L MPI. Does this temp seem too high with a 160 degree thermostat? I am assuming that the thermostat is 160 as that is the temp that I understand is stock for this motor (raw water).

 

[Don S]

Re: Alpha 1 Gen 2 Shaft seal question

The normally run in the 170 to 175 range, 180 means something just isn't right, not an overheat, but not right. Did you have the vanes of the impeller going the right way when you put the pump together? New gaskets and sealed properly? Face seal installed correctly?

 

[Paxdad]

Re: Alpha 1 Gen 2 Shaft seal question

I believe so. The vanes on the impeller were oriented with curves to the right (( if looking at the impeller and housing turned upside down. I marked their orientation prior to removing the old impeller however as I mentioned the shaft seal was not installed on the shaft when I removed it so therefore the old impeller could have been in backwards. I installed the plate and gasket the same way the old items were removed. When you refer to the face seal are you referring to the shaft seal on the shaft that goes down on top of the water pump housing?

 

[Paxdad]

Re: Alpha 1 Gen 2 Shaft seal question

I believe so. The vanes on the impeller were oriented with curves to the right (( if looking at the impeller and housing turned upside down. I marked their orientation prior to removing the old impeller however as I mentioned the shaft seal was not installed on the shaft when I removed it so therefore the old impeller could have been in backwards. I installed the plate and gasket the same way the old items were removed. When you refer to the face seal are you referring to the shaft seal on the shaft that goes down on top of the water pump housing?

Just wanted to follow up on my OP. I ran the boat after work yesterday and the highest temp on the gauge was 180 degrees after a 4800 rpm run for a mile across the lake. At idle speed <1000 rpm it stayed at 175. I believe all is well but will check to make sure the thermostat is or has not been changed from stock 160 degree to a 180. Otherwise it runs great.