Water & exhaust ? in gear case !!!!

[kajnjim]

1977 25hp Johnson 25R77S<br />I've got water and what looks to be possibly exhaust in the gear case. Changed clutch dog and noticed water in the gear case after taking it out on the water, so I re-sealed the case and added new gear lube. Put it on the water again and then drained gear case to see if that fixed it. Had water again and this time noticed dark grey substance that had settled to bottom of otherwise clear gear lube. Recently serviced water pump. Made certain that housing and plate were well sealed. Is there anyplace else that water/exhaust may be getting from exhaust housing to gear case? Maybe where the drive shaft enters the gear case? Any ideas?<br /><br />Thanks,<br />Jim

 

[Goodoleboy]

Re: Water & exhaust ? in gear case !!!!

Could be the drive shaft seal is leaking. Did you put new plastic washers under fill and drain screws, Those are the most likley culprits.<br /><br />Exaust can not enter gear case, unless mabey its cracked. But thats not likley. <br /><br />Good luck!

 

[kajnjim]

Re: Water & exhaust ? in gear case !!!!

I'll pull it apart and check the drive shaft seal and see what I got. Drain and fill screws are good to go. Thanks alot.<br /><br />Jim

 

[MarkHPCA]

Re: Water & exhaust ? in gear case !!!!

I suggest you do a pressure and vacuum test on it as some of the seals are not visable but can leak.

 

[kajnjim]

Re: Water & exhaust ? in gear case !!!!

Took apart this am and inspected drive shaft seal. It was intact, but not real snug against shaft. It was also adhered to the metal where it was seated. Decided to go ahead and scrape it out and will replace. Thanks again.<br /><br />Jim

 

[kajnjim]

Re: Water & exhaust ? in gear case !!!!

OK, finally got around to doing pressure test. The only place that I lost air was the round indention below the cavitation plate that I'm guessing is a vent(can't find a reference to it in the OEM or Seloc manuals. Where to from here? <br /><br />Jim

 

[jameswilson95]

Re: Water & exhaust ? in gear case !!!!

it could be several possibilities...<br />there are only a few seals/orings which would allow anything into your gearcase.<br />Driveshaft seal, shift rod seal, spagetti seal, gearhead seal, and fill and drain plug seals.<br />If you pressure test your gearbox (i would suggest taking the gearbox of and take it to a marine technician for this because they will do it properly with the right tools). The black sediment that you see could very well be a seal which is breaking down, or even bearings which are breaking down. Put this sediment between yours fingers and rub your fingers together and try to determine what it is.

 

[kajnjim]

Re: Water & exhaust ? in gear case !!!!

James,<br />The sediment is long gone after draining and resealing the gearcase and hasn't returned. After putting her in the water again, I took a look at the gear lube. There was only the milky-looking oil. When I drained and resealed, I dropped the lower unit and replaced the drive shaft seal also. Didn't look at the shift rod seal though. The other seals were intact. Hmmm??? <br /><br />Jim

 

[MarkHPCA]

Re: Water & exhaust ? in gear case !!!!

 

[wilde1j]

Re: Water & exhaust ? in gear case !!!!

Do a proper vacuum and pressure test. Start by draining the gear oil. Pressurize to no more than 15 psig. Should hold some pressure for at least 30 minutes. Same with vacuum test. If it doesn't hold, put the LU under water ... bubbles will show where the leak is. BTW, there is no "vent" in the gearcase.<br /><br />Good luck!

 

[kajnjim]

Re: Water & exhaust ? in gear case !!!!

W1,<br />Been there, done that. That's how I found the air leak at what I'm guessing is a vent. Its not in the gear case, but a little higher, yet still below the cavitation plate, between the gear case and the water pump. That's why I'm guessing its probably a vent for the water pump, leading me to believe there is a problem with a seal above the gear case. Guess I'll have to do some more diggin'. Thanks.<br /><br />Jim

 

[blackwaterstout]

Re: Water & exhaust ? in gear case !!!!

Jim what have you found out about your problem? Sounds similar to mine. I have a 1979 Johnson 25. My fluid appears to be a little milky and it was coming from some vent hole that I wouldn't have expected it to. I took the top drain plug out of my gearcase and the lube that came out wasn't clear, it was slightly milky. Not exactly sure what to do now. I think it might have something to do with that Sierra water pump I put on a few weeks ago. It did not come with an installation diagram and I had to guess at how to put it on. It was different from the water pump I took off. I'm not sure if I got the o-rings in the right place.

 

[kajnjim]

Re: Water & exhaust ? in gear case !!!!

BWS, took it out a couple of days ago and haven't had a chance to drain and check yet. I may do that tommorrow and I will post the findings. Oh, since last post, I have replaced that drive shaft seal. Will cross my fingers as I drain and see what happens.

 

[blackwaterstout]

Re: Water & exhaust ? in gear case !!!!

When you replace the lube and run and then take it on how long do you typically run it for? I'm gonna do that with mine tomorrow morning but I don't want to overwork it enough to damage it in case there is something wrong.<br /><br />Was the driveshaft seal hard to replace?

 

[kajnjim]

Re: Water & exhaust ? in gear case !!!!

BWS, I always run in tank of water for about 15-20 minutes after replacing lube and then check for any obvious leaks before taking the boat out. From launch to my favorite spots on the river are no more than 30 minutes anyway. Definitely don't want to bugger up the gears. They sure aint cheap. The drive shaft seal was very easy to replace. Didn't really need a seal puller. Just used a big screwdriver and a little leverage. Used a spark plug socket and hammer to gently tap the new ones in place. Be sure to get two. Then install them facing each other. You'll notice that when you take the old ones out.

 

[blackwaterstout]

Re: Water & exhaust ? in gear case !!!!

Okay thanks Jim. I noticed when I was installing my water pump that if I pulled up slightly on the drive shaft that gearcase fluid would come out from the seals slightly. Is this normal? I figure if gear lube came out of the seal water can get in huh?<br /><br />Thanks for mentioning that there are two seals there. I forgot about that until I looked at the parts diagram. Sure enough there are two seals. If advance auto doesn't stock them then I'll have to order them. I do not have a marine distributor anywhere near me.<br /><br />I've heard of doing a pressure test but I doubt I have the right equipment. I have access to an air compressor but I do not have an attachment to screw into the drain hole. Is there another option for pressure testing the gearcase?

 

[itstippy]

Re: Water & exhaust ? in gear case !!!!

Get an old valve stem from somewhere - anyplace that sells tires will give you an old one, they replace about a hundred a day. Whittle it down with a pocket knife until you can screw it into the fill plug hole. Don't use an air compressor, use a bicycle pump. You only want about 10 lbs of pressure. Otherwise you'll just blow the seals you're trying to test.

 

[kajnjim]

Re: Water & exhaust ? in gear case !!!!

I did basically what itstippy said, but I used the tubing from my gear lube pump. This will allow you to see obvious leakage if you have it under water, unless you have a pressure gauge and can see if it holds pressure over a few minutes.

 

[kajnjim]

Re: Water & exhaust ? in gear case !!!!

BWS, didn't get a chance to drain and check lube today.(Had to replace PTO shaft on bush hog instead-higher priority right now). Promise I will though, and let you know. Let us know the results of your pressure test when you get something rigged up.

 

[blackwaterstout]

Re: Water & exhaust ? in gear case !!!!

That trick with the old valve stem seams pretty slick. I will be sure to try that out if it comes to pulling the lower unit again. I want to try replacing the washers on the drain and vent holes first.