Water in the lower unit

[apsanford]

I have a 1968 Mercruiser 120 in my Sea Ray SRV 185. I'm getting water in the 80-90 gear lube in my lower unit. The oil is milky after a couple hours, and it leaves a light oil film in the water. If I refill the unit with fresh oil, and let it set, no leaks show up below the unit (out of the water). I plan to refrubish the prop so I was going to reseal that part, behind the prop, and replace all the o rings on the fill and vent screws. What about the water pump? It seems to cool fine, so that part works, but could the seals or gaskets leak water into my lower unit? Any suggestions will be great, as I'm new in the boater world.

 

[Nickledimed]

Re: Water in the lower unit

Something I would like to know also.
How hard is it to replace the seals, what seals, on a lower unit....I have a bigfoot merc.
Maybe this should be in the motor section?

 

[SeanT]

Re: Water in the lower unit

For what its worth - I had this problem on my old IO. Turned out to be a slightly bend prop shaft. Very difficult to notice, but it was indeed bent. It was easier to see the bend rolling it on a table than spinning the prop.

Out of the water, pressure tests on the lower unit were fine, but in the water, prop spinning, the leak would occur.

 

[zbnutcase]

Re: Water in the lower unit

Could also be a rusted shift shaft if its still original.

 

[apsanford]

Re: Water in the lower unit

I took it over to a local marine dealer and discussed the issue with the mechanic, he is sure it's the seals, and I ordered what was advised, about $60 in seals, and he advised it was quite simple to disassemble and reassemble. Being a old auto mechanic and new in boats, I'll give it a try. If anyone has some tips, I'm still open for suggestions. This boat sat on the trailer for 5 years in a garage, before I bought it, so I'm sure the seals are dryed out anyway. I have a Seloc manual, but I'm not impressed with it. #3200 Mercruiser Stern Drives 1964-91 repair manual
Thanks for the info so far. I think this is a Type 1 Stern Drive??? Serial # 2331206

 

[Nickledimed]

Re: Water in the lower unit

Can you take pics and steps to do this?
Greatly appreciated...Cisco

 

[ks_artist]

Re: Water in the lower unit

I have a similar setup (1965 Mercruiser 110 HP with IA E-Z Shift stern drive) with a similar issue (milky oil in lower unit after an hour or so of use). It?s down on my list of things to fix, but that list is slowly getting shorter.

Apsanford- Please let us know the success of replacing your seals. I have the same Seloc manual you have, and it?s not nearly as detailed as the PDF Mercruiser service manual that used to be posted to the Adults Only section (which Don S had to remove due to copyright issues). PM me if you never got a chance to download this.

Zbnutcase- Could you elaborate on how a rusted shift shaft could cause this issue? Every time I remove my lower unit, there?s water standing in the cupped shift shaft area. Don?t know if this is normal or not, but could it be leaking down the shift shaft into the lower unit gear lube?