Merc 3.0, Alpha One lower unit oil leak

[illiad]

A few years ago my wife and I inherited a 1990 Glastron with a Mercruiser 3.0 / Alpha One (first gen). I made the stupid mistake of running the boat on the trailer, in gear, so that I could adjust the idle mix on the carb. Needless to say, sand on the ramp + impeller = work on the lower unit. I have replaced the pump and housing on the lower unit and it is pumping water like a champ now.

Problem # 1:The drive oil is leaking out through the weep hole on the fore end of the lower unit. I noticed the leak when I was changing the drive oil as I pumped the fresh oil in through the drain plug on the lower unit. I ran the motor for a minute to make sure that the water pump was functioning properly and now I have milky drive oil (water in oil).

Problem # 2: I can't get the gear shift shaft on the upper unit set right. I can get the lower unit into the proper gear, but how do I know when the upper unit is in the correct gear? So far I have gotten all neutral (put the washer back on the shift shaft after that) and now I have forward, forward (in neutral), and cannot shift to reverse.

I suspect that the biggest problem is going to be #1, #2 will, I think, be trial and error, but any advice will be helpful.

 

[illiad]

Re: Merc 3.0, Alpha One lower unit oil leak

Could the problems be related? Shift shaft leaking due to misalignment? If I take the lower unit off and start filling it with gear oil from the drain plug, where should I see the oil come out? I am thinking that this might help me track down where it is leaking and if it is the upper or lower unit.

Any an all help appreciated.

 

[cr2k]

Re: Merc 3.0, Alpha One lower unit oil leak

You should always be in forward gear to remove/replace drive or lower.

Put control in forward. Tilt lower forward put ccw pressure on prop. shift shaft should be facing straight forward.

Leak could be seal damage either from water pump base or shift shaft.

Did you replace the quad ring on the lower?

 

[illiad]

Re: Merc 3.0, Alpha One lower unit oil leak

I replaced both the upper and lower parts of the water pump along with all of the gaskets. If it was a leak from the water pump, wouldn't the oil be coming out of the water intake on the unit? I also replaced the quad ring on the lower unit. I have the shift shaft on the lower unit in forward (same as cr2k's directions) but apparently it isn't lining up right. Is this looking like the shift shaft seal? Is there any way that I can test it before taking the shift shaft apart? I have to drive at least an hour to get to any boat parts stores, so I like to know what parts to get before I head out of town.

Thanks

 

[illiad]

Re: Merc 3.0, Alpha One lower unit oil leak

The manual says that there is supposed to be a rubber washer under the Stainless Steel washer on top of the bushing. I don't think this is the problem, but I do not have a rubber washer under the SS one.

 

[illiad]

Re: Merc 3.0, Alpha One lower unit oil leak

Ok, took the lower unit back off today and tightened the bolts on the water pump just a little more, then started filling the lower unit with oil to see if I could find the leak. I filled the lower unit with oil until it came out through the galley passage between the lower and upper unit (where the quad seal is located). After much aggravation, I got the lower unit back on the upper unit with the shifter lined up correctly (YAY!), bolted everything together nice and tight and started it up with gear oil. Everything was just fine until almost one quart of oil was in and it started pouring out through the same drain hole again.

Question: Is there more than one passage that the oil is supposed to use to go between the upper and lower unit, or is it just the one oil galley with the quad seal?

I'll try to post pictures later. Please help, I'm sure I'm not the only person to have this problem before. Please help!

 

[Bondo]

Re: Merc 3.0, Alpha One lower unit oil leak

Question: Is there more than one passage that the oil is supposed to use to go between the upper and lower unit, or is it just the one oil galley with the quad seal?

Ayuh,... There's only the 1 passage, but the Upper has a couple of Seals as well....
My guess is, it's a seal in the Upper unit...

 

[illiad]

Re: Merc 3.0, Alpha One lower unit oil leak