FW Pump Leaks again. 3.7 Mercruiser

[MikeeH]

1988 Mercruiser 3.7, closed cooling. AF was dripping from the weep hole on the stator cover last season so I replaced the water pump shaft seals in the spring before launch. All good for about 50 hours this season before the leak returned but worse than before my repair. Neighbor says the problem is scoring on the shaft where the old seals were seated so I need to install the new seals backwards so they don't ride on the same spot on the shaft. Does this make sense? Is there a shaft sleeve that can be installed to fix the scoring issue? I really don't want to find that I'll need to do this a third time. TIA.

 

[stonyloam]

NO!!!! If you install them backwards THEY WILL NOT SEAL! Seals are designed to stop flow in one direction in this case from the cooling system. On the 470 pump you need to instal a Speedi Sleeve http://www.skf.com/us/products/seal...als/wear-sleeves/skf-speedi-sleeve/index.html over the grooved area of the cam. That will give you a new sealing surface. When you instal the new seals BOTH seals must be installed with the garter spring facing away from the block, toward the coolant. Do a search here, lots of guys have done it.

 

[alldodge]

1988 Mercruiser 3.7, closed cooling. AF was dripping from the weep hole on the stator cover last season so I replaced the water pump shaft seals in the spring before launch. All good for about 50 hours this season before the leak returned but worse than before my repair. Neighbor says the problem is scoring on the shaft where the old seals were seated so I need to install the new seals backwards so they don't ride on the same spot on the shaft. Does this make sense? Is there a shaft sleeve that can be installed to fix the scoring issue? I really don't want to find that I'll need to do this a third time. TIA.

Agree don't install the seal back wards, it's like leaving the door open in the winter.

Just go get another water pump and make sure it is a marine type

 

[stonyloam]

Just go get another water pump and make sure it is a marine type

Dodgeman, no can do on a 470, the pump impeller is bolted to the end of the camshaft and there are a couple of seals that keep the coolant out of the crankcase, so the repair is to sleeve the cam with a Speedi sleeve and replace the seals.

 

[alldodge]

Dodgeman, no can do on a 470, the pump impeller is bolted to the end of the camshaft and there are a couple of seals that keep the coolant out of the crankcase, so the repair is to sleeve the cam with a Speedi sleeve and replace the seals.

My bad, sorry I try real hard to completely stay away from 470 questions (slipped and wasn't hard enough this time) , and I didn't notice the 3.7 so my apologies to all

 

[Bondo]

I try real hard to completely stay away from 470 questions

Ayuh,... Same here,... the 470 is a horse of a different breed,....

 

[stonyloam]

So true, so true LOL!

 

[MikeeH]

Thanks all. I'll break it down and look more closely at the shaft to see if its possible to clan it up with some emory cloth or I will need a sleeve. I love the old boat but she's showing her age.