Seal orientation

HPwannabe

Seaman
Joined
Feb 15, 2020
Messages
63
Hi all,
I’ve searched the forum and found one or two related posts, but I’m still confused on this. I’m replacing the seals in the upper housing on my alpha 1 gen 1. My manual (which is really for R/MR, up to 1983) says that the lower seal should have a lip facing toward the driven gear - in other words upward. But there is a much viewed video by Wayne Coll in which he says to face the lip (what he calls the spring side of the seal) down - toward the exhaust/water side.
I’ve always heard lip towards what you’re keeping in/out. So Wayne’s method seems right. This would also mean the upper seal lip should go up (which he also advises). My manual doesn’t even cover that one.
Can someone set this to rest and provide a solid reference? I tried to take pictures when I disassembled but it’s been a while and now the pics aren’t obvious and I’m second guessing everything.
Thanks.
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,292
The lower seal helps keep water out of the shaft splines ,most are spring upwards. THe upper oil seal must face the gear spring side up
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,366
Hi all,
I’ve searched the forum and found one or two related posts, but I’m still confused on this. I’m replacing the seals in the upper housing on my alpha 1 gen 1. My manual (which is really for R/MR, up to 1983) says that the lower seal should have a lip facing toward the driven gear - in other words upward. But there is a much viewed video by Wayne Coll in which he says to face the lip (what he calls the spring side of the seal) down - toward the exhaust/water side.
I’ve always heard lip towards what you’re keeping in/out. So Wayne’s method seems right. This would also mean the upper seal lip should go up (which he also advises). My manual doesn’t even cover that one.
Can someone set this to rest and provide a solid reference? I tried to take pictures when I disassembled but it’s been a while and now the pics aren’t obvious and I’m second guessing everything.
Thanks.
Both seals are spring side up. Yes, counterintuitive. Listen to Wayne or listen to mercruiser...
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
...Can someone set this to rest and provide a solid reference?...
The Mercruiser factory manual solid enough? Here's a grab from manual #6...

The upper seal (installed from the top of the housing)..
1632631887343.png

And the lower seal (installed from the exhaust cavity)
1632631941993.png

Now, something else we need to discuss. The 'O-ring' at the top of the lower drive shaft. DO NOT install it. If you do, then there is a 50-50 chance that as the top of the drive shaft passes through the seal, the O-ring will foul on the seal, which will pull half of it out of the groove, and hold the seal open. When that happens, water WILL enter the shaft spline cavity and very quickly rot out the splines in the bottom of the upper drive shaft. Merc fixed that problem on later drive shafts. They don't have an O-ring groove.
1632632204331.png

Chris........
 

HPwannabe

Seaman
Joined
Feb 15, 2020
Messages
63
Clearly I need to get my hands on a newer manual. But this one agrees with my manual on this point.
Thanks for the info.
 
Joined
Mar 27, 2010
Messages
3,008
Maybe your using a Clymer or Seloc? The Mercruiser manual was issued quite a few years ago, my version says '97. You can get the pdf version HERE
 

HPwannabe

Seaman
Joined
Feb 15, 2020
Messages
63
Maybe your using a Clymer or Seloc? The Mercruiser manual was issued quite a few years ago, my version says '97. You can get the pdf version HERE
Yes, unfortunately, I have an old Seloc manual. I can't seem to get to any of the links people have sent for the Merc manual. My computer is a little over-protective at times.
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,366
Yes, unfortunately, I have an old Seloc manual. I can't seem to get to any of the links people have sent for the Merc manual. My computer is a little over-protective at times.
Sometimes, if you believe in her very much, the manual fairy will visit you...

Edit: did Eric's links not work for you?
 

HPwannabe

Seaman
Joined
Feb 15, 2020
Messages
63
Sometimes, if you believe in her very much, the manual fairy will visit you...

Edit: did Eric's links not work for you?
Ah, yes, now it looks like I can get there. I forgot I am running a VPN that sometimes interferes with things.
thanks,
k
 
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