1970 ol' Mercury 650 lower unit

[bietau85]

So I had my boat stored outdoors all winter and when I drained the lower unit I had about an ounce of water that came out along with about 20 or so ounces of oil. Should I be concerned of a bad seal or could there be a way for condensation to do this? The motor has rarely been used the last 4 years. Might be 10 hours on it. Any insight? Im concerned because my old motor caught fish line and blew the unit and I dont wanna jeopardize this motor as its a pretty sweet sounding machine. Thanks...

 

[carholme]

Re: 1970 ol' Mercury 650 lower unit

Just flush it, replace the oil and the seals on the Fill/Drain and Vent screws and run it. If it was mine, I would be replacing the impeller as well. Run it for a few hours and re-check the oil to see if it is taking on water.

If you are really worried about it, you can always pressure test the LU.

Gerry

 

[bietau85]

Re: 1970 ol' Mercury 650 lower unit

Yea I already have a rebuild kit coming in the mail as last year it was poorly flowing water during last start up. However in regards to the LU I am gonna flush/fill after impeller gets installed and cross fingers for the best and check after first run.

 

[racerone]

Re: 1970 ol' Mercury 650 lower unit

If the lower unit is original it has a carbon steel driveshaft, not stainless as current motors.------What happens is the shaft rusts right where the oil seals ride on the shaft.-------Lower units / gears are expensive to repair.----Seal kits and a speedi-sleeve are cheap.

 

[bietau85]

Re: 1970 ol' Mercury 650 lower unit

Funny you mention that racerone, I went to replace impellar today and the oil seal on the base of the housing has a gouge out of it, I now know where the water came from fortunately. $20 from local marina to press in a new oil seal. Prolly the smallest bill ive ever had at a marina.

btw what is a speedi-sleeve? The shaft on my LU is very clean, i think it was onced over before I got it. I found it odd though that the impeller was backwards after removal. Obviously explaining the poor water flow because the impellar was very hard compared to the new one but no damage to it. My thought is that he PO replaced impellar incorrectly and let it sit that way for awhile and it never slung back into the correct position, if thats even possible...