Alpha One Oil Leak

[Slice of Life]

I discovered a slow but steady oil leak from my Alpha One Gen two outdrive after starting it up for the first time this season. The leak was found through the small seep holes on both port and starboard sides, as well as trace amounts out of the water intake holes. I mistakenly parked the outdrive in the up position while it's been on the trailer (yes I now know this is a big no no) if that has relevance. I've read the stickys regarding finding leaks and have been investigating, but so far from what I can tell found nothing conclusive on the location of the leak. Also, when the oil was drained I did notice some white streaks in the old oil which also is probably an issue I'm reading.

Pressure testing the lower unit first at 10 PSI with my Mityvac after draining the oil and plugging the outlet where the oil goes through with the red seal, it held pressure, and I also tried the soapy water method but finding no bubbles. Taking the water pump impeller off looking at the black seal carrier, gaskets and plate under the impeller housing I found gear oil. I changed the water pump impeller kit last season and debating on changing it again.

The upper unit was found to be more difficult to test but after plugging the oil hole I could only find air coming out of the water tube or around it possibly, I will try to look at it more. Here are some pics of the oil that I found. Also reading common sources of these leaks are the shift shaft bushing and shift rod bushing assembly, but again, no air leaking out of the assembly, and looking at the shaft bushing there was no signs of oil.

I'm waiting to get this leak resolved before putting the drive back on as I just replaced all of the bellows and shift cable assembly and really really hope I don't have to take the bell housing off again. Thanks.

 

[achris]

Re: Alpha One Oil Leak

You need to put the upper and lower back together and pressure test them as a single unit. Only then do you have a chance of finding a leak. The reason is because the upper needs the lower drive shift installed into the upper drive shaft to be a sealed unit.

I also noticed in the photo of the bell housing the upper shift shaft and the shift slider are completely devoid of grease... They need to be greased, preferably with 2-4-C...

Chris....

 

[Slice of Life]

Re: Alpha One Oil Leak

Ok, joining them back together then pressure testing...but how do you find exactly where the leak is when they are back together and cannot see exactly where the air is leaking when it's all closed up? And I cleaned the shafts of the old grease is why they seemed greaseless, I will be putting 24C on before I put the drive back in. Thanks

 

[achris]

Re: Alpha One Oil Leak

If you leave the water pump housing and base plate out, then you can see the top seal of the lower housing through the exhaust cavity...

 

[Slice of Life]

Re: Alpha One Oil Leak

Interesting, ok I will try that and try to look in the exhaust cavity. Most videos on Youtube show each part being tested individually but they were also able to show easily a leak using soapy water, apparently from a leak that was very significant. I'm almost ready to just give the outdrive itself removed from the boat to a mechanic and have them find and fix the responsible seals as this becoming quite frustrating. Or, I could simply throw new seals that are likely culprits on it and keep testing it to see it if still leaks. Thanks.

 

[Slice of Life]

Re: Alpha One Oil Leak

Ok, I put the units back together and it obviously won't hold pressure, where air is coming out of the exhaust cavity. The problem is knowing where exactly the leak is coming from. The videos that are made for pressure testing make it look so easy. I'm putting in a new shift shaft bushing and carrier seal assembly with a new water pump kit with new seals and hope that does the job.

 

[achris]

Re: Alpha One Oil Leak

If it's the exhaust cavity it could be the seal between the housings, the lower seals in the upper housing or the the top seal in the lower housing (the one that normally lives under the water pump). All those seals are accessible from the exhaust cavity. Just squirt the soapy water at each in turn and see what gives....

Chris......