Alpha one gen1 drive shaft housing lower oil seal question

[Cali_Boat_Guy]

Twin 260 hp 5.7s and twin Alpha One Gen 1 SS drives. One drive serial number is A638982. I have seen a few videos and posts that say the lower oil seal in the drive shaft housing is supposed to be installed lips down. However, Service Manual No. 6 says both the upper and lower oil seals should be installed with the lips up "toward the top of the housing". The reason usually given for installing the oil seal "lips down" in the videos or comments is to "keep the water out". It seems to me that water would not enter either way. Does anyone know why it is recommended (by some) to install the lower oil seal lips down?

 

[nola mike]

Twin 260 hp 5.7s and twin Alpha One Gen 1 SS drives. One drive serial number is A638982. I have seen a few videos and posts that say the lower oil seal in the drive shaft housing is supposed to be installed lips down. However, Service Manual No. 6 says both the upper and lower oil seals should be installed with the lips up "toward the top of the housing". The reason usually given for installing the oil seal "lips down" in the videos or comments is to "keep the water out". It seems to me that water would not enter either way. Does anyone know why it is recommended (by some) to install the lower oil seal lips down?

You install the lips in the direction of the stuff you're trying to keep out. If I were designing it, I'd install upper seal lips up to keep oil in, and lower seal lip down to keep water out. However, Merc would apparently rather you get water in the drive rather than lose oil, so they recommend both seals face up. As usual, if my choice is between listening to Mercury engineers vs. a random YouTube yahoo, I choose Mercury mostly

 

[Cali_Boat_Guy]

You install the lips in the direction of the stuff you're trying to keep out. If I were designing it, I'd install upper seal lips up to keep oil in, and lower seal lip down to keep water out. However, Merc would apparently rather you get water in the drive rather than lose oil, so they recommend both seals face up. As usual, if my choice is between listening to Mercury engineers vs. a random YouTube yahoo, I choose Mercury mostly

Thanks Mike! I've read of folks removing the O ring from the lower drive shaft to avoid problems with the lower oil seal installed lips down. Maybe it isn't a problem if the seal installed lips up? If I installed an axle seal with the lips in toward the 90 wt. oil (to keep it in) then I wouldn't expect water to get inside the axle seal from the outside either. Who knows?! I'm leaning toward the Mercruiser engineers on this. Thank you for the feedback!

 

[dubs283]

Most oem drive double seals have been upgraded to a one piece containing two seals. Virtually impossible to install incorrectly

 

[Cali_Boat_Guy]

Most oem drive double seals have been upgraded to a one piece containing two seals. Virtually impossible to install incorrectly

Good to know! If that's the case then I like my odds. Thank you!

 

[nola mike]

Most oem drive double seals have been upgraded to a one piece containing two seals. Virtually impossible to install incorrectly

Hmm, last I did it a couple of years ago that wasn't the case. That would be a better solution

 

[todhunter]

Dang, twin SS drives?! Those things are hens teeth.

Agee - follow Merc's instructions and keep those drives alive.

 

[Cali_Boat_Guy]

Dang, twin SS drives?! Those things are hens teeth.

Agee - follow Merc's instructions and keep those drives alive.

Hey Todd. Thank you for the input. I've been putting some money into both drives. New yokes, seals, water pumps, etc. It is starting to add up. If I need any major parts at some point then the SEI drives will be very tempting (cost wise). The gear ratio would be the pretty much the same (1:50), however, I don't know if the SEI drives would hold up or perform as well. Thanks for the reminder about keeping these drives alive. I'm committed to saving them right now.