3 Lower Unit Problems

[Evinrookie]

Changing the gear lube in my newly purchased 67 Evinrude 80Hp, I found 3 issues.

1. More water than oil came out when I drained it. This is normal right?....No?....Didn't think so. The gaskets seem to be in good shape. Are there any common places that are prone to leaking? The prop has a little play in it before it feels like it's catching. Is this normal? How can I check for where the leak might be?

2. There is a notch where the lower gear housing meets the upper gear housing (Picture 1). Is this supposed to be there or did somebody pry too hard with a screwdriver?

3. There is a little hole below one of the bolts on the upper gearcase housing. It has a slow leak but it is not gearcase lube(Pictures 2 & 3). It appears to be unburnt 2-cycle. Would this little hole be letting water into the lower unit? Does this look like a job for JB Weld?

 

[iwombat]

Re: 3 Lower Unit Problems

The most common place to develop leaks are through the fill/drain plugs. Have you been replacing them with every lube change? Next likely is probably the prop shaft seals. Take off the prop and look behind for any fishing line, etc.

In order to really tell what's leaking, you'll need to pressure test the LU in a tub of water.

Don't know if that hole is normal, but it's not in a spot that would cause water intrusion.

 

[Evinrookie]

Re: 3 Lower Unit Problems

I've only taken the boat out once and this is the first time I changed the gear lube. The fill/drain plug seals appeared to be pretty tight and I replaced the o-rings when I changed the lube. Could the prop shaft seal be bad even if no fishing line is present? If so, how do I replace the seal or is this something I need a professional for? How do I pressure test the LU?
Thank you for the feedback.

 

[72SideWinderSS]

Re: 3 Lower Unit Problems

Looking at Pic number two, it appears that the Oil Level Plug has been sheared off. That would be where I would suspect water intrusion.

 

[F_R]

Re: 3 Lower Unit Problems

The rectanguar hole is a normal drain hole. So is the other one. Don't be plugging them up. I'm not 100% sure, but the round one might be an indicator of a drive shft seal leak..I'd have to look to be sure.

There are only a few places the gearcase can leak:
1. The drive shaft seal, or the bearing housing holding the D/S seal
2. The prop shaft seal, or the bearing housing holding the P/S seal.
3. The shift rod seal
4. The seal between the upper and lower gearcases
5. The fill/drain plugs
6. The gasket or o-ring on the shifter pivot phillips screw.

All but the drive shaft seal and shift rod seal can be plainly seen just by looking at the outside.

 

[HighTrim]

Re: 3 Lower Unit Problems

To pressure/vacuum test a lower unit:

a) drain the gear oil
b) use an appropriate adapter with a gauge tee'd in to apply pressure or vacuum. No more than 15 psig for pressure. You can use a bicycle pump or any other compressed air source for pressure. For vacuum, you need a vacuum pump.
c) LU should retain some pressure or vacuum for 45 minutes minimum.
d) If pressure doesn't hold, submerge LU in water to find leak source [possibilities: drive shaft seal, prop shaft seal(s) (usually two), shift shaft seal and the fill/drain screw washers.]
e) replace offending seal(s) as required.

 

[rudedude]

Re: 3 Lower Unit Problems

Looking at Pic number two, it appears that the Oil Level Plug has been sheared off. That would be where I would suspect water intrusion.

I'll bet that right there is your problem or at least one major one.

 

[Evinrookie]

Re: 3 Lower Unit Problems

So far I'm liking what I'm hearing FR. From what you're telling me and what I've seen it looks like the first thing I should do is replace the prop shaft seal. Do I have to drop the LU to change this seal or can it be reached by simply removing the propeller? I have a SELOC but it doesn't always have the clearest instructions. Here is the parts breakdown of my LU. "http://www.crowleymarine.com/brp_parts/diagrams/38427.cfm" There are lots of things described as seals, gaskets, o-rings, etc. Which would you recommend replacing?
I'm sure glad I heard from you before I started going JB Weld crazy on that thing.

72Sidewinder - I took the picture while changing the lube and had the oil level plug out.

 

[Evinrookie]

Re: 3 Lower Unit Problems

Thanks HighTrim,
I wouldn't have thought of using a bike pump. I guess that would be the safest way to avoid blowing a seal that isn't already bad.

 

[dajohnson53]

Re: 3 Lower Unit Problems

I've only taken the boat out once and this is the first time I changed the gear lube. The fill/drain plug seals appeared to be pretty tight and I replaced the o-rings when I changed the lube. ....

You've gotten great advice from others who know more about water leaks than I do. The only comment I'll make is based on my own experience. You mention "O rings" for fill/drain seals. Make sure those fill and drain seals should actually be O rings, not some other seal such as fiber or nylon washer/gaskets. Just because previous owner used O rings doesn't mean they are what is supposed to be used. It is important to use the correct device - and your dealer will have the ones for your motor and they are cheap. The incorrect device is likely not to seal properly.

You also should CHANGE them every time you change the lube. THey can look just fine, but some are made to be used only once, and won't seal properly the second time. Buy a bunch and just treat them as one-time, disposable items.

That said, if you're actually getting water out of there after one use - as opposed to just evidence of moisture in the lube (milky, but still pretty much oil), that to me indicates a larger source of water intrusion than the fill/drain seals.

 

[Evinrookie]

Re: 3 Lower Unit Problems

Thanks for the correction. They are nylon gaskets. I don't actually know if all that water came from my 1 use. I bought the boat a little over a month ago and didn't check/drain the LU lube before taking it out. The lube that came out was gray and milky and pretty nasty. When I first pulled the drain plug I thought the previous owner might have filled it with diesel (nope just nasty smelling water) because I heard you can run that to flush the gear case. Then the actual lube started pouring out and I knew I was in trouble.

Maybe my gear case is special and uses an equal parts water and gear lube mix!

And I agree with you that I've got some great advice from these guys. I would be up the creek without an outboard without this site.

 

[HighTrim]

Re: 3 Lower Unit Problems

You could also flush the lu with kerosene before putting in the new lube. Most dealers in my area throw me a handfull of the seals when I go in, and as dajohnson stated, use them one time only. I use the thicker hard plastic type, but from the amount of water you found, i doubt your leak is from the gaskets. Water is heavier than the oil, that is why is sinks to the bottom of the lu, so when draining always pay close attention to the first bit that comes out.

 

[iwombat]

Re: 3 Lower Unit Problems

Before you go replacing any seals, drop the LU and pressure test it. You're just wasting your time doing anything else. You can also bring it to a shop and have them pressure test it. You'll pay something for it, but it'll save you the hassle of finding or creating a tester.

 

[Evinrookie]

Re: 3 Lower Unit Problems

I actually sell oil skimmers for a living and was expecting a little water to come out when I pulled the plug but I got more than a little.

iWombat,
You say to "drop the LU and pressure test". Is this correct? Do I have to drop the lower unit to pressure test it? I guess I just assumed I would test it while still assembled. If I do need to remove the lower unit first how do I plug the opening for pressure testing?

 

[iwombat]

Re: 3 Lower Unit Problems

Hrm . . .

Well you could pressure test it while it's on. If it's the prop shaft seal you'll be able to see the bubbles come out. If it's anything else, they'll disappear up the exhaust housing and you won't. The lower unit is sealed up all on it's own you don't need to plug anything. (Maybe I'm not understanding your question.)

 

[F_R]

Re: 3 Lower Unit Problems

So far I'm liking what I'm hearing FR. From what you're telling me and what I've seen it looks like the first thing I should do is replace the prop shaft seal. Do I have to drop the LU to change this seal or can it be reached by simply removing the propeller? I have a SELOC but it doesn't always have the clearest instructions. Here is the parts breakdown of my LU. "http://www.crowleymarine.com/brp_parts/diagrams/38427.cfm" There are lots of things described as seals, gaskets, o-rings, etc. Which would you recommend replacing?
I'm sure glad I heard from you before I started going JB Weld crazy on that thing.

72Sidewinder - I took the picture while changing the lube and had the oil level plug out.

The prop shaft seal may be semi-difficult or it may be some-what difficult to replace, depending...

Remove the propeller and look. Can you actually SEE the seal, or is it inside? Either way, the gearcase head has to be removed in order to get the seal out. To do that, you remove the 4 screws and use your flywheel puller with some very long bolts to pull it out. Now comes the fun part. If it is the kind you can see, it can be knocked out and replaced. However if it is the kind you cannot see, the bearing has to come out, and will be destroyed in the process. That means you need a seal, a bearing, a special tool to remove the bearing, an o-ring around the outside of the gearcase head, and four o-rings for the screws. It is just about cheaper to just replace the whole gearcase head.

Then you need a couple of guide pins to reinstall the gearcase head.

Have I talked you out of it yet? Like I said, do you see any oil running out from around the shaft?

My money is on the drive shaft seal being the culprit. But that's a guess.

 

[Evinrookie]

Re: 3 Lower Unit Problems

iWombat,
Thanks for the quick reply. I'm sorry, I'm new to outboards and didn't realize the gearcase would still be sealed up once I removed it. It makes sense about not being able to see a drive shaft seal leak. Any idea what type of fitting I will need to give it some air?

 

[Evinrookie]

Re: 3 Lower Unit Problems

You are very wise FR and I take back what I said about liking what I'm hearing. And yes, you've talked me out of it. Sounds like by the time I buy the bearing removal tool, flywheel puller (if I can even find the right one), and all the parts needed for the job, I could just as easily take it to a repair shop.
It's hard to tell if there is a leak at the prop shaft because the unburnt 2-cycle that was running out of the vent hole behind my water intake dripped all over the prop and I can't tell if what's around the shaft came from there or not.

Is the drive shaft seal any less difficult? I'm sure I'll be doing an impeller/water pump replacement soon and from the diagrams I've seen it looks like it's in the same area.

 

[iwombat]

Re: 3 Lower Unit Problems

For a fitting . . .

If you get one of the LU lube pumps it comes with a fitting you can remove and hose clamp to an air pump.

 

[Evinrookie]

Re: 3 Lower Unit Problems

Great! Thanks iWombat