Alpha 1 Gen 2 Upper Seal Issue?

WileyOompa

Cadet
Joined
Jul 6, 2018
Messages
8
Hey all, I am having an issue and I am trying to determine if this is what I need to do. I have a 2004 Mercruiser 4.3 with the Alpha One Gen II outdrive. I have pulled the lower unit off 3 times to replace pieces to try and figure out this leak issue.

I have had the boat shop replace all the seals around the impeller and shift housing. They told me those are the most likely culprits of my leak. Today once it warmed up, I am still getting gear oil dripping. It is specifically leaking from the starboard weep hole in the lower unit. I am suspecting this issue is an upper housing seal but I dont want to be buying parts until I figure it out. Any assistance would be much appreciated. I have the #14 manual for my outdrive so I am fairly confident that I can do all this myself but I dont want to be chasing problems without some more experienced advice.

I have been looking for videos and how to’s on this particular issue and cannot find anything specific to this issue on the Gen 2, I have found 1 or 2 where they are doing the Gen 1 or someone is doing an entire upper rebuild. I would like to avoid pulling the entire thing off the boat. Can it be done by just pulling the lower and removing the cap on the upper?

All help is much appreciated. I have been chasing this issue since Friday before Memorial day.

Thanx!!!
 

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dubs283

Vice Admiral
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Jul 27, 2005
Messages
5,322
You need to pressure test the drive assy. Only way to be sure which seal(s) are leaking
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,284
Did you replace the small Quad seal between the units. I doubt is the upper shaft seals and no the drive comes off, apart and the seals push up and out from the bottom
 

WileyOompa

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Joined
Jul 6, 2018
Messages
8
You need to pressure test the drive assy. Only way to be sure which seal(s) are leaking

The boat shop pressure tested the lower unit and told me all the seals in the lower unit are replaced and good. Is there a pressure test for the upper unit?
 

WileyOompa

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Joined
Jul 6, 2018
Messages
8
Did you replace the small Quad seal between the units. I doubt is the upper shaft seals and no the drive comes off, apart and the seals push up and out from the bottom
Is that the little orange o-ring that goes in the little hole on the lower unit before you put them together?
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,350
The boat shop pressure tested the lower unit and told me all the seals in the lower unit are replaced and good. Is there a pressure test for the upper unit?
Not on a gen 2. Pressure test the drive when it's together.
 

WileyOompa

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Joined
Jul 6, 2018
Messages
8
Not on a gen 2. Pressure test the drive when it's together.
With the upper and lower units together, the air would leak out wherever the leak is, correct? How do you figure out what is bad if the 2 units are together and you cannot tell where the leak is? I imagine I could hear it leaking but if the seal inside is leaking, how do you know which one?
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,350
With the upper and lower units together, the air would leak out wherever the leak is, correct? How do you figure out what is bad if the 2 units are together and you cannot tell where the leak is? I imagine I could hear it leaking but if the seal inside is leaking, how do you know which one?
There are only 3 seals in the upper, and the input shaft seal would leak into the bellows. The other 2 would be replaced as a pair.

I have replaced that and made sure its in place. Also, I think if that was the issue, the gear oil would more likely leak between the 2 halves of the upper and lower unit would it not?
It could leak anywhere depending on the attitude of the drive, but yeah, should see it between the drives esp if tilted on the side. Also should be obvious if you pressure test drive.
 

Rick Stephens

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Joined
Aug 13, 2013
Messages
6,118
A soap/water solution in a spray bottle will show leak(s) right quick
What he said.

You can see just enough of the upper gear case output shaft to spray soapy water on it - usually. I had to dunk a drive in a water trough to find a leak once, so I won't disparage anything that makes me look like Sherlock Holmes.
 

WileyOompa

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Joined
Jul 6, 2018
Messages
8
Well I had my boat guy who has been assisting me with the maintenance and repair of my boat look at my drive for the 3rd time. He said he would put money on the upper shaft seal being bad. He has pressure tested the lower and the entire unit.

I will be tearing it all apart tonight, hopefully the parts are home when I get there. Going to record the entire thing as I have not been able to find a decent video on replacing the upper shaft seal in a GenII unit.

Will let you all know how it goes and will share the video once its uploaded.

Thanx
 

hegemon_tim

Recruit
Joined
Jul 25, 2022
Messages
1
Well I had my boat guy who has been assisting me with the maintenance and repair of my boat look at my drive for the 3rd time. He said he would put money on the upper shaft seal being bad. He has pressure tested the lower and the entire unit.

I will be tearing it all apart tonight, hopefully the parts are home when I get there. Going to record the entire thing as I have not been able to find a decent video on replacing the upper shaft seal in a GenII unit.

Will let you all know how it goes and will share the video once its uploaded.

Thanx
Any chance you made that video? I'm chasing a similar leak. Thanks!
 
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