Merc 650 gear oil leak!!!

[almost_nick]

ok guys, I have a 75 merc 650, and there seems to be gear oil leaking into the lower end where the water pump and shift shaft is. I put brand new seals on the water pump, and New gaskets. I also put new seals in the shift shaft bushing. I checked the seals and the lower end for cracks and rough places but everything is smooth. AND STILL THERE IS OIL LEAKING!

Also when I drain the plug for the gear oil. there dosent seem to be much water mixed, It seems like oil is somehow getting pushed up through the waterpump or shift shaft, but water is not going down into the gears??

Please help!

 

[Moody Blue]

Re: Merc 650 gear oil leak!!!

Sounds like one or more seals may be installed upside down.

That would allow fluids to pass in one direction and not the other.

 

[almost_nick]

Re: Merc 650 gear oil leak!!!

Umm. I didnt think about that. The seals in the water pump are factory installed because I bought a new one. and I followed the directions on the seals for the Shift shaft. Im pretty sure they are put in correct.

Is there anything i can buy that would show where exactly it is leaking from??

 

[Fuzzytbay]

Re: Merc 650 gear oil leak!!!

One thought, is there too much oil in the gear housing?

 

[almost_nick]

Re: Merc 650 gear oil leak!!!

Good thought, but im putting oil in the bottom untill it just comes out the top vent. Hopefully thats not too much. But thats what i was told to do.

I think I might take the pump off and check the seal for the 5th time, just to closely exam the lower end for small cracks or anything that would let oil through.

Any other thoughts??

Thanks a lot guys, I just wana see this fixed. Hope to god I dont need a new lower end. that would break the bank for me.

 

[Fuzzytbay]

Re: Merc 650 gear oil leak!!!

Good thought, but im putting oil in the bottom untill it just comes out the top vent. Hopefully thats not too much. But thats what i was told to do.

Nope that the correct way.

I think I might take the pump off and check the seal for the 5th time, just to closely exam the lower end for small cracks or anything that would let oil through.

I'm not sure if this would work, but you might be able to put a bit of air pressure in the fill hole of the bottom end, and look from above to see if you can see where the oil is migrating up from.

Any other thoughts??

What weight oil are you useing? maybe a heavyer weight might help.

 

[lindy46]

Re: Merc 650 gear oil leak!!!

Get a pressure test gauge on ebay for about $30. Pump it up to about 10psi and listen for leaks/spray seals with dish soap solution and look for bubbles. If it holds steady at 10psi, seals are ok.