alpha one lower unit leak

[JerryIrons]

Greetings all, just thought I would post the leak I found in my lower unit, kind of interesting to some of us maybe. Last summer I started seeing evidence of water intrusion in my outdrive gear oil, the color started changing to light green when I changed it. Not too bad, but clearly water was getting in the oil so needed fixing. Also I noticed gear oil dribbling out of the prop area. First thing was to build a pressure tester, there are many out there but attached is the one I built. I bought the gauge at a chain auto store, it's a slime low pressure gauge that was cheap and only goes up to about 15 psi. Set up my drive in my stand, drained the oil, and pressurized it to about 12. I can hear a bubbling hiss somewhere, seemed like right smack in the middle of the drive. But I don't trust my old ears! Tried using my mechanic stethoscope, didn't help at all! Put some soapy water around the prop area and upper area, no bubbles, so I split the drive. Put my finger over the quad ring hole, pressurized the drive and can hear the gurgling hiss from the water pump base area. Pulled off water pump top part, and re-tested. Clearly it's the water pump base area now. The base doesn't seem cracked or anything, so pulled off my water pump base, and then I see the oil seals still on the drive and not with the water pump base. Air is bubbling up through between the oil seal and the shaft.

My 2nd picture shows the seals still attached to the outdrive, along with the pump base, somehow they got separated, ie ripped apart. It's hard to see because everything is dark, but I've circled in red the oil seal that is still on the outdrive. I flipped the water pump base over, and circled in yellow where the seal is supposed to be! you can see some of the seal top still on the base. At first I wasn't sure about if this was wrong, but found another post in here talking about the exact same thing happening. So thanks to everyone here because you guys helped me troubleshoot this.

Now I've got to figure a way to pull those seals off, probably try prying first without hurting anything, or even some small screws right into the seal and pull up. Oh the joys of boat ownership

Once I get the seals off I will try and get another pic.

 

[Bt Doctur]

The part you see in the lower unit actually belongs IN the base of the water pump
Do you have a spring loaded pin on the top of the driveshaft or no pin

 

[JerryIrons]

Yeah that's what I thought, it's supposed to be part of the base of the water pump. The service manual goes through putting new seals in the base of the pump, and then installing the base.

No pin on top, I have an alpha one, "generation one" drive

 

[Bt Doctur]

img hosting

 

[Bt Doctur]

The manual dosent really show the difference in the pump bases but there are 2 different types, with the preload pin and without the preload pin

 

[Bt Doctur]

new bases come with the seals installed

 

[JerryIrons]

yep I saw that as well, and they look similar but are different, so I'll be sure to order the right one (46-44292A3). Thank you for the confirmation, I don't feel like I'm winging it now!

Oh good I thought they might have seals, but wasn't sure.

 

[JerryIrons]

Here is a picture of the seal partway off. As you can see I used a small aggressive wood screw to help pull it up. That was my 3rd attempt, I pulled out the first 2, because I was unsure how deep I could go with one. Once I worked it out enough to get the o-ring off, I could put a little leverage in there under the lip with the right thickness flat head screwdriver on the other side. Thanks again bt doctur.

 

[achris]

Yeah, I've seen that before. That section, isn't supposed to come off the water pump base.

Also, you can now describe your drive as MR or Alpha One. The only difference between those 2 was the name. (Marketing 'dribble')... They are the same, inside and out...

See if you have a letter stamped into the end of the propshaft... If you find an 'A', then it's an earlier MR... Otherwise, later MR or Alpha One.

Chris........

 

[JerryIrons]

Huh, didn't know that thanks. No letter on mine so later MR/alpha one. Now just twiddling my thumbs while parts arrive.

 

[JerryIrons]

Just a last follow up to this, and to make you laugh, I put in my new water pump base (with seals already installed). Decided I wanted to pressure test it before assembling everything to save myself some work. Put my 12 psi of air in, hear hissss, whoops forget to plug the oil hole with my finger. Plugged the oil hole, put some air pressure on and hear pop, hisssss. The air pressure had popped the base up off the outdrive slightly, of course it did because nothing is holding it on! Took base off and looked over, seals seemed fine, put back on. Next I held both the base and plugged the hole, turned on air small amount and things seemed good. Put water pump housing etc back together, basically reassembled lower unit and pressure tested ok. So word of advice to future people make sure you re-assemble the water pump with nuts to hold things together haha. Put complete outdrive back together and air holding steady for 1/2 hour or so. So thanks to all who helped!