Lower Drive "Milkshake"

[pinecliff]

Would like some info on what would be possible cause for the lower drive oil on my '71 Evinrude "Triumph" 60hp to be taking water. It works OK but when I drained the oil to winterize it I got what looks like a milkshake. Is there an internal gasket or seal that would be the source ? The 2 external screw/plugs were tight, and I see no obvious cracks or external oil leaks.

 

[dafox99]

Re: Lower Drive "Milkshake"

Hi Doug. A common problem, I'm afraid. But, not terrible to fix if you are a bit on the mechanical side. You need to reseal the lower unit. There are various seals, gaskets and o-rings for the propshaft, driveshaft, bearing caps, etc. I believe that model may have a couple of solenoids in the front for shifting .. there is a gasket under the cover for those as well. Get a book if you are going to do it yourself. Some of the more experienced guys can tell you if you are going to run into needing any special tools for that particular model. It's been too long for me to remember .. some had some giant snap rings. When done, a 5 - 10 psi pressure check is needed to make sure everything is sealed. Good luck!

 

[dafox99]

Re: Lower Drive "Milkshake"

BTW, Doug, when you do it, or have it done, I'd recommend throwing a new water pump impeller in if yours is not fairly new. They're cheap, and since you have already pulled the l/u anyway, might as well replace that somewhat fragile, and very key part of the motor.

 

[JB]

Re: Lower Drive "Milkshake"

Doug. Did you put new gasket rings under the Drain and Vent plugs?<br /><br />The most common, and easiest to fix, cause of water in the gearcase is old gaskets or "O" rings there.

 

[pinecliff]

Re: Lower Drive "Milkshake"

There are supposed to be O rings on the drain and vent plugs? Obviously that would be the first thing to correct. The screws were pretty beat up, I imagine from being cranked down with too much force to compensate for the missing seals. <br /> How would I pressure test the lower unit? Seems like I would want to do that before I disassemble the unit, after I replace those O rings.

 

[Paul Moir]

Re: Lower Drive "Milkshake"

Usually about 10 or so psi. No more than 15. Definitly before you haul it apart - often it's helpful to know where the leak is before you take it apart.<br /><br />If there's a little groove underneath the oil plug's head, then they use a rubber o-ring. If they're flat under there, they use a nylon washer. If you use nothing they will certainly leak.<br /><br />Hope that helps!

 

[dafox99]

Re: Lower Drive "Milkshake"

Also, Doug, one of these guys .. I think Paul .. had me run diesel in the L/U for a few seconds and then drain before re-filling AFTER you get the leak sealed. I had the same problem as you, I pressured tested, and it held 10 psi for hours. I re-filled, ran it a bit, and checked it. It was milky again. The leak was fixed, but it turns out, it's tough to get all the emulsified oil out, and it mixes with the new, making it milky again. If you run some diesel in it for a few seconds, then drain, and re-fill (twice, probably wouldn't hurt), it cleans out the emulsified oil. Good luck.