Force 70 HP, leaks lower end

[Bruced]

It sounds as if this question has been asked before because I keep getting several answers. But, here goes. My Force 70hp keeps losing gear oil. I have changed the two prop shaft seals, twice. This time it doesn't seem as bad, but the last time, all of the oil leaked out after the second run on the lake. The leaking oil is clear, or blue in this case, meaning no water intrusion. After the last seal change, it seems to drip about two to three drops per day. The bearing looks to be fine and tight. Any ideas??<br />Thanks

 

[eurolarva]

Re: Force 70 HP, leaks lower end

You are going to have to make a pressure tester and submerge the lower unit in water and find where the air bubbles are coming from. You can make this a number of ways. one way is to use a lower unit oil pump that cost about 10 bucks and somehow hook it up to a tire pump. Insert this into the vent hole and then test for the leaks. I made one with a basketball needle and drilled a hole in an old drain plug and sealed it with rtv. Your leak could be coming from some place other than the bearing carrier. If the leak persists at the bearing carrier chances are your prop shaft is worn to the point where the seal cannot seal good enough.

 

[WillyBWright]

Re: Force 70 HP, leaks lower end

And I don't think eurolarva is necessarily talikng about the bearing as being worn, although that's a possibility. More likely the shaft has grooves where the old seals wore. Hard to get anything to seal once that happens.

 

[OBJ]

Re: Force 70 HP, leaks lower end

This is an outside shot, but check the prop shaft for burrs especially around the splines that may catch the seal and cause a cut in the seal rubber. I have found similar problems on a couple of occasions.

 

[Bruced]

Re: Force 70 HP, leaks lower end

So we went to lake this weekend and found water in the lower end. ARG! I have checked the shaft and can't find wear marks or burrs of any kind. So it looks like I need to try Eurolarva's idea to check for the leak with pressure. Obviously I don't need to put 110lbs of pressure on it to find the leak, but do you suggest a pounddage? Hope others aren't having this kind of problem.<br />Thanks<br />Bruced

 

[scotiany]

Re: Force 70 HP, leaks lower end

I'm suprised no one has mentioned the drive shaft seal and the shifter seal. Either of them are prime candidates for leaking on an older unit.

 

[eurolarva]

Re: Force 70 HP, leaks lower end

If it were me I would buy a seal kit for the lower unit. They cost about 30 bucks. Replace the seals that scotiany mentioned because they dont require the lower unit to be disassembled. Also replace the washers for the drain and vent plug. If you pressure test it you only need a few pounds of pressure. A bicycle pump will give you enough pressure.

 

[roscoe]

Re: Force 70 HP, leaks lower end

I read in my manual to use no more than 7 pounds of pressure.