Question re: Alpha One upper unit

[JASinIL2006]

Hi, I am helping a friend with a newly acquired boat, and last weekend we were changing the water pump. There was quite a bit of wear on the housing and it looked like the drive had been run without water a bit, we we replaced the whole pump housing, etc.

I watched achris's video on changing an Alpha One pump, and he noted that the water pocket cover in the upper assembly should be checked, too. Sure enough, there were signs of damage so we're going to replace that as well.

While inspecting the water pocket cover, though, we noticed something in the adjacent socket that receives the splined drive shaft coming up from the lower half of the outdrive. Looking into that section, it first appeared that some thick lube had oozed out from the part that receives the drive shaft. When we looked closer, though, it seems that an O-ring is broken and we were seeing one end of the cut O-ring sticking out. I'm assuming that O-ring serves some purpose and that we should replace it, but I'm not sure exactly what that assembly is or how to get at it.I looked up the drive on the Mercruiser catalog and it looks like might be part of the upper drive shaft assembly.

I'm trying to get the drive's serial number (and maybe a photo) to insure I'm looking at the correct parts, but assuming I'm correct that this broken O-ring is hanging out of that upper drive shaft assembly, how much of a job is it to replace?

Thanks,
Jim

 

[Bt Doctur]

If I understand your question ,that O ring is supposed to be installed on the driveshaft if the driveshaft has a groove.Pick the remains out of the upper housing and install a O ring on the driveshaft.

 

[JASinIL2006]

There still was O-ring on the driveshaft when we split the drive. This was sticking out of the area that receives the driveshaft when you put the two halves together.

I think the O-ring that you are referring to is the one that they say we no longer need, is that correct?

 

[Bt Doctur]

Then someone failed to remove the O ring that was still in there the last time it was serviced. If it has the groove, use the O ring.

 

[thumpar]

I never used that o-ring on mine even though it had the groove. There have been more problems using it than not.

 

[Alumarine]

Does the O ring you found look the same as the one on the drive shaft?
If not, it might be part of the oil seal that's up there. If it's part of the seal it won't have a round profile like the O ring.

 

[JASinIL2006]

Does the O ring you found look the same as the one on the drive shaft?
If not, it might be part of the oil seal that's up there. If it's part of the seal it won't have a round profile like the O ring.

It's my buddy's boat, so I'm not to just run outside and look. I can check next time I can get out there. I sort of suspected that it might be part of that upper assembly. I'll see if I can find out about the profile of that ring and see if it might be part of the seal or if it's just an old O-ring that got left up there. Thanks for the idea!

Jim

 

[johnzonh]

had the same deal on my boat with an older alpha one...have the groove but no o ring...let it be. creates more havoc than needed.

 

[stonyloam]

I'm with marc on this, bet it is what is left of the driveshaft seal, # 10 here https://www.mercruiserparts.com/Sho...br=80&bdesc=DRIVESHAFT+HOUSING+AND+DRIVESHAFT Shine a light up there and take a look. Pretty easy to replace if the upper is off.

 

[JASinIL2006]

That's kind of what I was thinking... If that's what we're seeing, how involved is the repair? I'm guessing you have to go at it from the top (e.g., by removing the cover assembly?

Thanks!

 

[stonyloam]

It has been a few years, but as I recall, the driveshaft housing (upper) was off and just stuck a long screwdriver in through the exhaust and popped it out, and drove a new one in from below. Do not think you can do it from the top. You should pull the upper anyway to check the gimbal bearing and lube the driveshaft and u-joints.

 

[Alumarine]

You don't have to remove the top. Split the halves and pop it out with a screwdriver like stony said.

Here's some more info. It is literally a 5 minute job once you have the drive removed and split.
http://forums.iboats.com/forum/engi.../7699146-alpha-one-water-impeller-replacement

Check to make sure there isn't a groove where the seal rides on the shaft.

Before I split the halves I put some painters tape around the drive shaft right under the seal. I figured that might help me figure out if I had to reposition the seal or not.

 

[JASinIL2006]

Thank you all! My friend is under the weather, but as soon as he's back on his feet we'll take a look at it. Thanks again!

Jim