87 2.3l OMC, water in gear oil, leaking from weep hole

After taking the boat out several times this year without issue, I noticed some gear oil leaking out of the upper weep hole after parking the boat after our last outing. I removed the drain plug and quite a bit of water came out before any oil came out. This is the only boat I have ever owned and have not had any issues before this so, it is new territory for me.

I have read several threads on multiple sites and most suggest bad seals/o-rings, or a crack somewhere. Can I assume that since we had the boat out several times without any leaking oil that it isn't a crack and just a seal or o-ring has gone out? Are the likely culprits in the Lower unit? And would running on muffs help determine if the leak is in the lower unit? I have also read replacing seals in the lower is much easier then the upper, so would much rather it be a lower unit seal.

I did replace the impeller last year, could I have not sealed something correctly that would cause this?

Thanks for any help!

Remove the prop. see any fishing line around the shaft, will look like a melted plastic washer.

If yes then that seal is gone, you just might get away with replacing just that one.

You should pressure test the drive.

http://www.ebay.com/itm/Outdrive-Lo..._Accessories_Gear&hash=item417493b435&vxp=mtr

Upper weep hole? Where's that?Pic? Most times??? the unit leaks at the drain plug seal.You change them when you changed the oil? The plastic OMC's are a 1 time only use,should be thrown away after using once.I use Mercruiser seals,unless they are o-rings. Like Master said,check the prop for line and drain and pressure test.Fill out the profile? You might be close to someone who can help test the drive.

Jerryjerry05 said:

Upper weep hole? Where's that?Pic? Most times??? the unit leaks at the drain plug seal.You change them when you changed the oil? The plastic OMC's are a 1 time only use,should be thrown away after using once.I use Mercruiser seals,unless they are o-rings. Like Master said,check the prop for line and drain and pressure test.Fill out the profile? You might be close to someone who can help test the drive.

Click to expand...

I don't have a pic, but it is a tiny hole above and to right of the water intake screen. There are actually 2 of these holes, one above and one below the screen on the starboard side. they allow water to drain out of the lower unit. The top is the one that I noticed gear oil oozing from.

I'll remove the prop and see whats in there up. If that seal is bad wouldn't it be leaking there too?

Ok, took off the prop and notice the large rubber seal inside the prop had been pushed down and wasn't seating against the large metal washer. The seal around the prop shaft didn't look so good either, but was intact although it looked like it might have some cracking.

Now, here is where I think I found at least one problem. I removed the cover that covers the impeller housing and noticed some water leakage around the seal, so figured I might as well pull it off, clean it up and get a new gasket set to replace it. After pulling the housing off i noticed a seal around the impeller shaft that was pushed in on one side and out on the other side. There was even a spring like peice showing. Milky gear oil was also on the shaft. I'm assuming that this is probably my main problem. Now, how to go about fixing it? Is it a seal that has to be replaced from the other side after pulling the upper case from the boat? Are there two seals here?

Thanks again for any help.

Another update. I finally found in my manual how to change the seal. After removing the impeller housing there are 2 more bolts behind it that hold on what the book calls an adapter. The adapter is suppose to come off by grabbing the adapter inside the water inlets with vise grips and pulling out while jiggling up and down/side to side. This is a no go for me. This thing is stuck and I'm afraid my pliers are going to mess something up...... Any suggestions on how to remove this thing, doesn't look like it has ever been removed as it looks like there is original paint over the edges....HELP!

You don't want to use a slapper puller, slow steady pressure with a spanner puller.

I have a bunch of different ones acquired over 45 years i see in harbor freight alot of different ones and if i don't have something to slip
( blind ) i make something up maybe a real thick washer cut flat opposite.

Your going to get a complete seal kit ? I would. Cheaper.

Well, looks like I'm going to bite the bullet and try to find a shop that will work on this for me. I doubt anyone local has the seal kit I'll need. My question is do the Lower Unit seal kits come with the seal that goes around the impeller shaft? Could someone post me a link to the exact kit I will need to address any possible seals that would let water in the gear oil? Will a lower unit seal kit cover everything I'll need or do I need an upper seal kit too?

Master mechanic said:

You don't want to use a slapper puller, slow steady pressure with a spanner puller.

I have a bunch of different ones acquired over 45 years i see in harbor freight alot of different ones and if i don't have something to slip
( blind ) i make something up maybe a real thick washer cut flat opposite.

Your going to get a complete seal kit ? I would. Cheaper.

Click to expand...

What is a spanner puller? I don't see anything that might work searching for that term!

I don't see how that tool will pull this off this plate to remove the seal.

Look at this.

http://www.marineengine.com/parts/o...er=OMC+Stern+Drive&section=Upper+Gear+Housing

It's not just the plate. See the adapter behind it ?

See the shaft ?

Thank you jerry i didn't bother to look for a pic.


I got a better idea get the biggest hammer you can find like a 2 handle sledge and hit it like cheating wife.

Master mechanic said:

Look at this.

http://www.marineengine.com/parts/o...er=OMC+Stern+Drive&section=Upper+Gear+Housing

It's not just the plate. See the adapter behind it ?

See the shaft ?

Thank you jerry i didn't bother to look for a pic.


I got a better idea get the biggest hammer you can find like a 2 handle sledge and hit it like cheating wife.

Click to expand...

That pic is my pic, the thin metal plate that backs the impeller has already been removed.

The adapter is what I'm trying to remove. The seal around the shaft is bad, pressure testing just blows air out from around the shaft. I need some actual useful advice on how to remove the adapter so I can change the seal. The manual directions are not working, I'm about to thread the holes, attach some bolts and put a slide hammer to it.

Since it's gonna be a bugger??Vice grips,a hammer, a can of PB Blaster and a small propane torch. Spray and heat,tap with the hammer,TAP,not hard,then spray again,then heat,tap and spray.Do this a couple of times. Then vice grips on the piece. Your gonna ruin the o-rings but it will come out. The other way is to disasemble the drive and drive it out from the inside.

I gave up and just removed the upper unit and slide the yoke and gear assembly out. I should have done this a week ago, but I was afraid there would be more moving parts to replace. Now just waiting on my seal kit to come in and hopefully everything buttons back up without any issues and pressure test goes good. We shall see.

Got everything pulled apart, seals replaced and put back together. Boat trip yesterday went smooth, and no signs of water in gear oil, and no leaking.

Only things I had trouble with were finding something to put the impeller shaft seal in, it calls for a special tool, but I figured out a jack handle from a 2-ton floor jack works perfectly.

Also, I had a heck of a time getting the drive shaft/yoke back in. I thought it was the splines not lined up, but the u-joint section was binding in the bellows, once I got that figured out it went right in.

Thanks for the help, hopefully there won't be anymore issues.