2 cycle 9.8 water pump question

[98Ultrasport]

I'm working on a '71, 9.8. Naturally the impeller was bad so I thought I'd just replace the whole pump. The replacement arrived and the bottom housing seal is installed upside down, that is to say the lip is pointing OUT. I know the TOP seal is installed this way but on my original pump, the bottom seal is installed with the lip IN toward the water side of the pump. The parts manual APPEARS to show the seal installed as the original was... lip up toward the impeller.

Can anyone confirm which way the seal is supposed to go? Was there a production change that turned the seal over for some reason? It would SEEM that the lip should go toward the water side to prevent the water (at higher pressure than the gearbox) from making it into the gearbox.

Thanks for any help,

Steve

 

[98Ultrasport]

Well, by way of closing this thread out in case someone elese ever needs the information, since I received no responses to my question, I ordered a complete, original Mercury (Quicksilver) water pump. I figured that way, I'd know FOR SURE how the seal was supposed to be installed. The OEM pump has the seal in the bottom part of the pump (the side closest to the gear box) installed with the seal lip IN toward the water pump side (water side) of the pump. In addition, the seal, which is of course has the Mercury part number on it, is different than the non-OEM seal that was in the replacement pump I had before. The seal has a MUCH wider sealing surface on the lip, probably to be SURE no water can get from the pump side into the lower unit. In fact, the sealing surface is so wide that the ID of the seal APPEARED like it might be TOO SMALL to fit over the shaft but the shaft in fact, fits very nicely through the seal and the pump. After seeing the difference between the after market pump and the OEM, I'm very glad I got an OEM pump.

Incidentally, should anyone need the information, the TOP seal is installed with the lip OUT, toward the top of the pump.

 

[tpenfield]

Thanks for the follow-up (even though you got no replies ) Do you have any pictures to post as a comparison of the 2 water pumps?

I have the smaller brother to the 9.8 (a 1969 7.5) and have done several water pumps over the years. I just don't recall the orientation of the seal. It seems to me that the impellers on these pumps need replacing every few years . . .

 

[98Ultrasport]

I think you're right about the impellers but that's not a big deal to replace. In my case, it had been so long since the engine had been run, I wanted to "reseal" the lower unit, thus the new seal required for the water pump. I ordered a replacement pump and it LOOKED like the seal was installed wrong and comparing it to an OEM pump, confirmed my suspicions. Interestingly, if you look at places like Fleabay or Amazon, you can find pictures of the seal both ways.
I have already returned the defective pump so I have no pictures but if you look at the bottom housing of the pump, the seal lip should be pointing IN. In fact, another way to think of it is BOTH seals in the water pump face the same way, with the seal lip pointing UP.

 

[markhodges78]

Should be a double lipped seal or 2 seals on both housing since it needs to block fluid from both sides.. In which case it wouldn't matter which way it was facing because it seals from both sides

 

[98Ultrasport]

Nope. The OEM seals are single lip seals. That's the way the seals were in the origainal pump as well. No double lips. You can see in the picture the new, OEM pump seal. The bore appears much smaller than the clearance hole through the steel housing because the seal surface is so long.