Alpha One Gen II shift shaft seals

MichaelBC

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Feb 28, 2020
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Hello,

I did use the search function but could not find anything about this topic. So if there is a thread about this already please guide me there.

Yesterday I removed my Alpga One Gen. II drive and found a lot of salt in the area of the shift wire. In my oppinion this should not be there and I would like this area to be dry.

5.jpg

I suspect the shift shaft to be leaking in there and removed the bearings and the seals. I did put this in new 2 years ago and now the lower bearing was very loose and wiggeling around the shaft.

4.jpg

The two seals at the top came out wet, even the boat was not in the water for almost a year now.

2.jpg3.jpg

I odered the complete set new alreay (shaft, bearings and seals).

What I am worried about is the direction of the seals. Just for my feeling I would put them in with the U form facing open towards the water side. But in the Mercruiser manual they are both open towards the dry side and this might be the reason why water comes in. Could this be a mistake in the manual or should this seals really be set in both in this direction ?

1.jpg

So I would like to hear the oppinion of the experts here how I should set in the new seals.

Regards

Michael
 
Last edited:

alldodge

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I agree with your assumption, the lip should be toward the water so it will have a better chance of sealing

Similar issue with seals and the B3 prop shaft. Early (manual 11) has 2 seals and states to place seals in facing each other. First (inner) lip faces out and Second (outer) faces in. Newer (manual 28) changes it to a single seal which has 2 seals in one (opposing each other)

I might tray to do same thing
 

MichaelBC

Petty Officer 2nd Class
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Feb 28, 2020
Messages
110
Thank you for your reply. If the U openings are facing each other then every liqiud going in would be trapped in there ?

I would have done it just the other way round and face the inner one inside and the outer one outside, or face both outside as there should be nothing inside to keep there.

I have maual 14. If anyone has a newer one for Alpha One Gen II then it would be nice to check if this shows the same picture or if this was changed.
 

alldodge

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Good point the B3 has oil on one side and water on the other.
 

flashback

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Jun 28, 2002
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3,987
I found that no seal can survive the exhaust heat when the water passage in the exhaust elbow is clogged.
 

flashback

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We can safely assume that the exhuast ellbows are clear and water is coming through. So this seals did not overheat.
Assume,, I've seen shutter burn out from lack of cooling. Shift shaft then over heats
 

Scott06

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Apr 20, 2014
Messages
6,724
Hello,

I did use the search function but could not find anything about this topic. So if there is a thread about this already please guide me there.

Yesterday I removed my Alpga One Gen. II drive and found a lot of salt in the area of the shift wire. In my oppinion this should not be there and I would like this area to be dry.

View attachment 377223

I suspect the shift shaft to be leaking in there and removed the bearings and the seals. I did put this in new 2 years ago and now the lower bearing was very loose and wiggeling around the shaft.

View attachment 377227

The two seals at the top came out wet, even the boat was not in the water for almost a year now.

View attachment 377225View attachment 377226

I odered the complete set new alreay (shaft, bearings and seals).

What I am worried about is the direction of the seals. Just for my feeling I would put them in with the U form facing open towards the water side. But in the Mercruiser manual they are both open towards the dry side and this might be the reason why water comes in. Could this be a mistake in the manual or should this seals really be set in both in this direction ?

View attachment 377224

So I would like to hear the oppinion of the experts here how I should set in the new seals.

Regards

Michael
This is how mine were factory installed and i replaced them in the same manner last year when i did my bellows. Normally i believe the spring goes to the side you want to keep sealed so this is correct

also make sure the bushings are replaced
 

MichaelBC

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Feb 28, 2020
Messages
110
Assume,, I've seen shutter burn out from lack of cooling. Shift shaft then over heats
I did understand that, but my impeller is good and the ellbows are almost new (arround 40 hours). I also have a pice of transparent hose where I can see the water flow and I check this at motor start twice a week. So there is no lack of cooling.

This is how mine were factory installed and i replaced them in the same manner last year when i did my bellows. Normally i believe the spring goes to the side you want to keep sealed so this is correct

also make sure the bushings are replaced

I did check some internet pages and they all say that the spring side is facing the side with the higher pressure or the liquid that you want to keep out. All parts are ordered and will be replaced.
 

MichaelBC

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I have a brand new shaft and a brand new bearing.
Is it normal that it looks like this ?
 

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MichaelBC

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The upper one is a little better but far from good. So it is no big surprise that the seals do not seal properly.
 

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MichaelBC

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No, they are seperate and will be set in the bell housing.

But the upper bearing also has a remarkable play and the seals are right below that. So if there is a possible movement of this shaft there will be no good function of the seals.
 
Last edited:

alldodge

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Then looks like the original bushings are probably just as good as the new ones. Its all up to the seals.
 
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