How do i fix Alpha One Gen 1 lower unit leak?

[RDJuhl]

Hi,
I purchased a 1989 Larson used boat (3.0 engine) which is powered by a Mercruiser Alpha One Lower Unit...I believe it is a Gen 1.
Lower Unit Serial Number 0C787706 (I believe this is a Alpha One Generation 1 unit)

We have had a small lower unit leak from the weep hole since we purchased it. I took the lower unit to a repair shop who pressure tested the lower unit. He identified the leak as below the water pump. It took him several attempts to seal it...trying a combination of old and new water pumps and gaskets. He finally told me it was fixed, and held pressure. I paid him $100 for this repair.

About a month later, I was prepping the boat for a launch, and ran it on muffs in the driveway. Lower unit oil was "oozing" out of the weep hole. I never did get the boat in the water this year...as I was afraid of doing some damage.

Time is now permitting me to winterize the boat...and hopefully, take care of this issue once and for all. I have received a Sierra Seal Kit 18-2652. I did pressure test myself today. It appears the base of the water pump is leaking again.

Attached are a few pics showing the lower unit, water pump, etc.

Question...why would the water pump not seal? What can I do differently from what the repair shop did?
Thanks for any advice!

 

[Dukedog]

gotta replace tha complete "base assembly" itself below tha pump along with tha seals.... part number 57234A 1 (maybe).....don't see it in tha sierra kit.. its tha part ya gotta pry out that has tha o-ring and drive shaft seal on it, gasket underneath .. also might replace tha shaft shaft seal while ya there......if ya do tha shaft seal take care NOT to let tha shaft itself come up with tha seal as ya unscrew it to remove.. it needs ta stay put so as ta save a few cuss words later on....