Alpha one leaking oil. But where to?

[tdagner]

Hi everyone, I have posted about this issue back in october of 2014, and havent begun to deal with it until now. I stored the boat for the winter and now that I want to get it out, i need to fix the lower units oil leak. Heres a link to the original post, but I will retell and update you on the specifics below.
http://forums.iboats.com/forum/engi...utdrives/8713851-mercruiser-alpha-1-using-oil

So my 2004 ebbtide 200 campione has the mercury 5.0 and alpha one outdrive with remote reservoir. This thing has ALWAYS used a little bit of oil in the lower unit. maybe a half a quart a season on the high end, but it was never leaking to the outside of the boat into the water, and wasnt leaking into the hull. towards the end of last season it started using a lot. I went through a quart in the last few months of riding, which got expensive. So I came on here and was told that the driveshaft was probably the culprit and that my bellows were prob full of oil. So, thinking that was the case I let the boat sit all winter, and decided to pull it off the lift and drag it home to fix last weekend.

I just got donepulling the outdrive, and while I can tell that it is leaking a little, there is no where near the amount of oil that I thought would come out of this thing. the bellows were clean, except for the grease that goes into the bearing in there. I have attached pics, please take a look and let me know if yall still think this is the driveshaft seal. it isnt leaking from the prop shaft seal, im pretty certain on that.

Its just that this is a lot less oil that I expected from seeing other pics online. theres no oil in the hull of the boat at all.

Give me your opinion. I have a service manual. The only part of changing the seal I am worried about it is setting the preload on the bearings once I go to put it back together, only because I have never done it before.

 

[tdagner]

Also, can someone give me a part number or tell me what this seal in the picture is called. I cannot find one for sale on ebay anywhere unless i buy an entire bellows kit. Which I dont want or need.

 

[Bt Doctur]

That is called the outdrive mounting gasket. Being a GEN II your oil leak is the lower unit driveshaft seal. You have what is called a "rotating leak" . Only loses a tiny bit of oil when the driveshaft is turning. Very easy to replace.

 

[achris]

That 'seal' is just part of the gasket. (27-94996A2)

To find your leak, you are going to need to do a pressure test. Look HERE for details. If you do need to pull the drive shaft out of the top housing and replace the seal, then have a look at the stickies at the top of the forum and follow your nose to the videos on how it's done. It's not at all difficult, just a little fiddly and you need an in-lb torque indicator (NOT a torque wrench)...

Chris.......

 

[achris]

That is called the outdrive mounting gasket. Being a GEN II your oil leak is the lower unit driveshaft seal. You have what is called a "rotating leak" . Only loses a tiny bit of oil when the driveshaft is turning. Very easy to replace.

I had a Gen II losing a very small amount of oil just recently. A pressure test revealed it as the UPPER drive shaft. Top box strip and replace the seal, all fixed.

The point being that there's more than one place a 'rotating leak' can occur, and a pressure test is needed to find out exactly which one. The alternative is to just buy a full seal kit and replace them all... Which is what I do anyway, but not before finding the culprit. No point in replacing just one seal if it means a full strip anyway.

Chris.....

 

[tdagner]

So i have looked at the link for performing a leak down test, and sure I can rig something up to do the job no problem. BUT, my question is how do you tell exactly where it is leaking from by performing a leak down test. Seems like the test will let me know there is a leak, but not pinpoint exactly where it is. Am I missing something here.

Thanks for all your help guys. time to order me some parts and find me an inch/pound torque indicator.

 

[Bt Doctur]

leakage between the upper unit and where the driveshaft enters will be obvious. you will see the bubbles or the oil dripping
same with the shift shaft seal, you will see bubbles or oil.
So see the lower seal you must remove the impeller and wear plate

 

[achris]

...., my question is how do you tell exactly where it is leaking from by performing a leak down test. ....

Spray bottle with soapy water in it...

Thanks for all your help guys. time to order me some parts and find me an inch/pound torque indicator.

Don't go buying tools and parts until you find the leak. If it's not the seal at the front, don't open it up unnecessarily.

Chris.......

 

[tdagner]

Thanks for the help guys. I have found the leak. It was leaking at the shaft where the water pump is. I popped the two pieces apart and gushing oil came out. Plugged the hole with my finger and could see air bubbles coming from around that shaft. I wont be pulling the driveshaft to replace that seal, I dont believe it is leaking since there was no oil in my bellows.

Time to look at the manual and see how to replace this seal.Hopefully its not to difficult.

I hate that this thing has been leaking oil back into the water, and feel bad about it. My impeller is in great shape, I guess because it has been so well lubricated over the years.

Any idea what caused this thing to leak. I know that it started leaking bad towards the end of last seaon after fourth of july. I had the boat loaded down that day, guess it added a little to much strain to the seal. any ideas? Any tips on replacing this thing? See the attached pictures.

 

[tdagner]

FIXED IT!!!! without buying a single new seal yet. See the below pic. Whoever assembled the thing on the line put the seal in sideways and not flush. So thats why it leaked from the get go. I pushed the seal flush and reinstalled, pressure tested and it no longer leaks. This thing must have been made on a friday at 4:45pm
All my troubles could have been fixed by one small strategically placed blow with a hammer on the assembly line.

Still got to buy one of those outdrive mounting gaskets cause I screwed mine up pulling the thing off. other than that, I should have this thing back together in a jiffy.

Thank yall so much for telling me to do a pressure test. If I had not, I would have replaced the upper driveshaft seal, put the thing back together and it still would have leaked. I would have not been a happy boater.

 

[achris]

...Thank yall so much for telling me to do a pressure test. If I had not, I would have replaced the upper driveshaft seal, put the thing back together and it still would have leaked. I would have not been a happy boater.

A little diagnostics goes a looooooong way... :thumb:

Well done on finding the problem.