Water coming through transom with gear lube

[1970 Chieftain V]

Hi all,

I finally started my 1970 Starcraft Chieftain. It has a Mercrusier 165 hp inline six with a model I outdrive. Water is coming through the transom above the coupler with gear lube in it. I was running it on the muffs to test before I give it a sea trail. The boat has set for about a year winterized. Any ideas?

Thanks in advance for your help.

Jason

 

[Don S]

Re: Water coming through transom with gear lube

Bellows is probably full of water and gear lube.
Pull the drive and check it............... Before going to the water.

 

[JustJason]

Re: Water coming through transom with gear lube

yep... its the upper driveshaft (input shaft) seal on the drive. usually have to replace both the seal and the yoke.

 

[1970 Chieftain V]

Re: Water coming through transom with gear lube

I took the outdrive off and found a missing oring. I can see where this would let water leak but not oil. I also drained the oil from the outdrive and refilled it. The oil was not milky color. Is it possible to overfill the oil and leak into the bellows?

I ran it this morning on the muffs for 30 minutes. Checked the oil level in the outdrive, it was still full.

Jason

 

[thrasher]

Re: Water coming through transom with gear lube

Could it have been old runny grease mixed in with the water rather than oil? Any water that gets into the bellows (from missing o ring) will pass through the gimbal bearing before appearing in the bilge. If you have not greased the gimball bearing in a while you might find the grease has got a bit runny and would mix with the water to give the water an oily look. Either way you need to repack the gimball bearing before the water completely damages the bearing..

Gary

 

[JustJason]

Re: Water coming through transom with gear lube

running on the muffs isn't going to do much... there is no pressure on the gears because even though they are turning.. they are not doing any work.
as they do start doing work, the oil will head up and pressurize the gearcase. if the seals cannot contain the pressure, then bingo... you got a leak.
always best to pressure test the unit.
if it is in fact gear lube (and not old grease as mentioned before) i'd bet you a jelly donut it's that upper seal... (they see the least lube so they are always the first to go)

 

[1970 Chieftain V]

Re: Water coming through transom with gear lube

running on the muffs isn't going to do much... there is no pressure on the gears because even though they are turning.. they are not doing any work.
as they do start doing work, the oil will head up and pressurize the gearcase. if the seals cannot contain the pressure, then bingo... you got a leak.
always best to pressure test the unit.
if it is in fact gear lube (and not old grease as mentioned before) i'd bet you a jelly donut it's that upper seal... (they see the least lube so they are always the first to go)

It sure smelled like gear lube. Sounds like I have another project to add to the list for this winter. It looks like the prop shaft seal maybe leaking also. I got the boat for free so I am already ahead of the game.

Thanks for your help.

Jason

 

[Don S]

Re: Water coming through transom with gear lube

It's very simple. The front seal in the drive on the ujoint yoke is there to keep oil IN, not water out. When water gets into the bellows, the drive heats up and cools and water gets sucked into the dirve. Then when it's run again it overfull and blows oil and water mix out the front seal into the bellows.
The yoke is also probably rusty and ground the seal away. Time to pull the upper apart and reseal the yoke.
Did you check your gear lube? Bet it's milky.

 

[1970 Chieftain V]

Re: Water coming through transom with gear lube

Time to pull the upper apart and reseal the yoke.
Did you check your gear lube? Bet it's milky.

What kind of special tools are involved? I am mechanically inclined but have absolutely zero merc special tools. I noticed looking around that seal kits for the upper and lower housings are fairly inexpensive.

When I drained the oil after the first incident it was milky but not after the second run.

Jason

 

[Don S]

Re: Water coming through transom with gear lube

Here is a link that will help.Yoke Seal Replacement

I would seriously suggest you find Merc SM #1 for your engine and drive since you are not familiar with that drive. Ebay may turn one up or if you have a super fast cable modem you can download manual #1 from this link. But it's 1.23 GB, (yea, that's GB, not MB) in size and will take a while.

http://www-alt.mercurymarine.com/mnetdata/sisdata/srvcovr.pdf