Water in the Oil in the Upper Unit - OMC 3.8L Stringer

When I first got my boat running on the muffs in the driveway, I checked the oil in the upper unit and it was milky. I noticed that there wasn't a seal under the head of the screw-in dipstick, and as the dipstick is right on top and the boat had been sitting for several years, I figured that it was possible that water had leaked in around the dipstick itself. Before water testing the boat, I drained and refilled the oil in the upper unit with BRP HiVis lubricant and added the correct seal. I tried my best to get all the old oil out and the new oil looked fine once I got the level correct.

After today's test run the new oil is milky again, so clearly I have a seal leaking somewhere.

According to my Seloc manual, (I know - but that's what I was given) I need to remove the outdrive, pressurize it to no more than 15psi, then submerge it to determine where it is leaking. Then replace the leaking seal.

Should I do that? Or given that this boat is 25 years old, the previous owner had it winterized only and did no other maintenance, and it hasn't been run for several years - am I better off to just replace all the seals in the upper unit as well as the impellor and anything else that is in there?
I don't want to sink too much into this boat, but once I'm in there it makes sense to me to replace all the seals the first time through and assume that new seals all around will resolve the current leak as well as preventing future problems.

Thoughts? I haven't priced the parts yet, but I'm not expecting the parts cost to be prohibitive and I'll be doing the work myself.

Anything to watch out for while doing the work?

Anything else to inspect, lubricate or replace while I have the outdrive off?

Thanks
Big_Eddy

Re: Water in the Oil in the Upper Unit - OMC 3.8L Stringer

Oh - and my kids want to know - if we change out the oil again, can we run it like it is for a 15-20 minute ride - or are we in do not drive condition?

Re: Water in the Oil in the Upper Unit - OMC 3.8L Stringer

I'm really glad your test drive went well. There is no telling how many hours we spent on lake Michigan when I was between 5 and 11 years old. Im 39 now, And i believe I can remember every minute that was spent there. We dont live there anymore though. My two kids and I plan on trying to make the same memories on the Tennessee river. Hopefully, your kids will enjoy it as much as you do. Oil leaks are usually pretty easy to fix. So good luck.

Re: Water in the Oil in the Upper Unit - OMC 3.8L Stringer

Any time you have water leaking into an oil area its prudent not to drive it all. Having said that, seals are cheap. Once you replace them along with all the gaskets you should be good to go. Then, you and the kids will really have blast.

Re: Water in the Oil in the Upper Unit - OMC 3.8L Stringer

check it again tomorrow - foamed up oil after a run looks a lot like milky oil

Re: Water in the Oil in the Upper Unit - OMC 3.8L Stringer

When i had my stringer, I replaced the 4 seals and both cup/cone bearings for less than $100. Took less than 2 hours the 1st time.

Re: Water in the Oil in the Upper Unit - OMC 3.8L Stringer

When you change the seals, be sure to closely follow all directions from the service manual. There are a number of sealants, anti-seize compounds & lubricatants required.

Its possible that you have a leak in your main bellows. They aren't very costly to replace if you're pulling the outdrive off anyway.

Re: Water in the Oil in the Upper Unit - OMC 3.8L Stringer

Howard Sterndrive said:

check it again tomorrow - foamed up oil after a run looks a lot like milky oil

Click to expand...

Here's a photo of the dipstick 24 hours after the last run. Doesn't look like normal gear oil to me, but it could be that some of the previous contaminated oil was still in there. It's hard to drain the upper housing completely. Looks like I have something to keep me busy over the next little while.

Re: Water in the Oil in the Upper Unit - OMC 3.8L Stringer

Bridar said:

Its possible that you have a leak in your main bellows. They aren't very costly to replace if you're pulling the outdrive off anyway.

Click to expand...

No bellows on a stringer drive.

Re: Water in the Oil in the Upper Unit - OMC 3.8L Stringer

I'd start with a prybar and check how much the exhaust housing/lower unit will float up and down on the upper gearcase.
There are shims under the top exhaust cap that should limit that travel to around .010"
It is easy for them to get misplaced or doubled up during swapping or repair of either half of the drive.
Then, I'd move on to a pressure/vacuum test.
TruCourse steering shaft is a common leak point.
Cracked uppers are fairly common too in the north. When ice breaks the water pump housing like most of us stringer owners have seen, it can also crack the case. I sold one on eBay recently, and then as I was packing it, I saw the crack....had to cancel the transaction.
If the drive has ever been stored tilted over the winter, ice can wreak havoc in there.