my leak in lower unit

(Second attempt to post this hope it's not dual post). O.K. guys, I finally can see where my gear box oil leak is coming from now. I rebuilt the entire lower unit. Put all new seals in and all new 'O' rings in where they belong. I ran the motor in my driveway for awhile, and today I checked the gear box oil to see the condition of it. It was like new still! I added some oil to the gear box just to make sure it has enough oil in it. I now see some of the oil coming out of a tiny hole in the lower unit ABOVE the gear box. It looks to be a vent hole of some type. If anyone has a SELOC repair manual for Johnson-Evinrude 1958-72 models, there is a good picture of the hole I am referring to on page 7-37, fig.157 (lower right in photo) and fig. 158 (bottom of part on the left side in photo). and a good shot of it on page 7-40 fig. 176 and page 742 fig. 184 to the right of the pinion gear in the photo.

The seals are all new. How can the gear box oil get up to the hole and run out? If I overfilled the gear box, would that cause the oil to bypass a seal and come out of that hole? I gave it a little bit "extra" oil when it came out of the top filling vent screw before I put the screw cap back in. It came out of the hole for a little bit then stopped. I ran it in the driveway again, and I got a small amount of water that dripped out of the hole this time. I rechecked the oil, it is clean, and i did not add any more oil to the gear box this time., but I still wonder how it got up to the level of the hole past the seals? Cuz' I overfilled it?

Re: my leak in lower unit

How can the gear box oil get up to the hole and run out?

Click to expand...

It can't.

Now, it would help if you told us what motor you are dealing with, but from what you have described I will assume that what you are seeing is simply unburnt oil/gas/carbon dripping down from the exhaust cavity and out a drain hole. This is a normal condition and happens more often when you are running the motor, without any load on it, in a barrel or on muffs.

Re: my leak in lower unit

Sorry. The motor is an evinrude 1962 40 h.p. model # 35933 selectric shift. It is definately not unburned oil from the exhaust. It is definately green oil that I just filled the gear box with and put the screws back into the fill hole and the vent hole when I filled it. The gear box oil came out of the tiny vent hole as described in my post AS SOON AS I PUT THE SCREWS BACK INTO THE FILL/VENT HOLES when I filled it, before I even ran the motor. I just wndered how can the gear box oil get past the new seals and O rings to bleed out of the tiny vent hole that is in the lower unit? Could it be because I overfilled the gear box??

Re: my leak in lower unit

Gear oil normally has a very specific smell. Get some on your fingers and compare it to what you filled the gearbox with and compare it to the oil you use for the fuel. The gear oil is usually much thicker as well. Hope this helps you decide what type of oil it is then you can decide a course of action. Good luck, Brian

Re: my leak in lower unit

It is DEFINATELY my gear oil that leaked from the tiny vent/drain hole. There is no doubt in my mind what is leaking, I am trying to find out if anyone knows HOW the oil got to that level, and I am wondering to myself if it can get up there by me overfilling the gear box with oil??? It is gear oil that is leaking out, but it has now stopped but I am worried that when I get out on the lake, I may run out of gear lube in an electric shift motor, so I am just trying to find out what I need to do if anything at all, or is it just beause I overfilled the gear box?????? Thanks Brian.

Re: my leak in lower unit

Run it in a barrel of water, fast idle, in forward.
Check the gear oil afterwards for water intrusion.
You will not run out of gear lube unless it is running out onto the floor as you fill it up.

Re: my leak in lower unit

Thanks whaler. I did that today after I seen the gear oil coming out of that little drain hole, and I ran it quite long too. I kept the host going into the container and i ran it in neutral, forward and reverse. I then checked the oil in the gear box. (did not drain it all, just a bit from the bottom) and it looked just like it did when I put it into the gear box, so I guess I am good to go. I just wonder if I got the oil past the lower drive shaft seal (or some other seal below that) by overfilling it with the pump applying a little pressure behind the oil too). Just a guess, but that's all I got).

Re: my leak in lower unit

Check it again tomorrow to be sure. Water will seperate from the oil and make its way to the bottom of the LU but it takes a little time. When you run it, the gears mix it up pretty good with the oil. Usually you can just open the fill plug (bottom one) with the vent plug still screwed in and any water should just drip out first, if you give it a day or two to seperate.

Now, unless the oil is gushing out, a little water in there is not going to destroy your LU instantaneously as long as most of it is oil. So run it and keep unscrewing the lower fill plug to verify no water and if that is the case, one has to assume that what you saw was exhaust gunk. If you do get water, then more investigation and work will be required.

Re: my leak in lower unit

Did you replace the shift rod O-ring? Gear oil can leak out there and run out the drain hole as described.

Re: my leak in lower unit

Thanks all. I did replace the "O" rings. There is no shift rod "O" ring as this is an electrict shift motor. The oil that leaked out again , was not exhaust gunk. It was green, freshh lower unit oil that came out immediately after I put it into the gear box. It was the same oil I just put into the gear box. Appreciate everyones input. Thanks.

Re: my leak in lower unit

The only other place it could get in that cavity is via the driveshaft seal.

Re: my leak in lower unit

Admittedly grasping at straws here, but...

Did you by any chance use a PRESSURIZED means to pump in fresh lower unit oil? If so, could the pressure have been high enough to dislodge something? Like the sealant used to secure the wires leading into the electric shift? <--Unlikely, but IF......... someone dropped the lower unit without first disconnecting those wires, then that might have broken the seal around the wires. Also. if while refilling you had the vent screw out then there shouldn't have been enough force to pop out the wire seal.

My old 135 Evinrude had electric shift, and as I recall the fluid it called for was more akin to automotive transmission fluid than to typical 'heavy oil' lower unit lube. <--Just a heads up.

Re: my leak in lower unit

Jim J Geezer,

You hit on something that I inquired about in another thread this afternoon. I asked if there should be a seal or something around the wires exiting the gearbox for the electric shift electro magnets? I tor the entire lower unit apart to replace the forward electro magnet and clutch hub. When I tore it apart, there was a lot of water in the gear box too. There was no sealant at that time around the wires. There is what is called a metal wire guard and a retainer that went in the hole, but it does not really seal the hole where the wires came out to go into the exhaust leg. What type of seal OR sealer has to go there? What is the purpose of the retainer? it does not seem to me that the retainer would stop water from goin in or oil from coming out. Is it missing a seal there? I did not put one in that location as there was none there when I tore it apart, and my repair manual (Seloc) does not indicate a seal OR sealer at the location. What needs to be done there??
NOTE: I used a hand pump that is made for the lower unit oil with hand pressure only while filling the gear case with the oil.

Re: my leak in lower unit

Maybe someone with a NEW electric shift lower unit can give you a definitive answer as to sealant type. My GUESS: epoxy

Re: my leak in lower unit

jim j geezer said:

Maybe someone with a NEW electric shift lower unit can give you a definitive answer as to sealant type. My GUESS: epoxy

Click to expand...

Jim,

Is there such an animal as a "new" electric shift motor? I think they quit making them back in the late 60's or maybe early, early 70's, but I am not sure. Epoxy sounds like it may work o.k. as long as I don't drip any into the gear case while applying it.That would not be good!! LOL

Re: my leak in lower unit

I just talked to a mechanic at a local Evinrude repair facility near me. Admittedly, he does not know too much about the electric shift motors, but he did tell me (after looking in the repair manual) that there is no seal required per manual at the location where the wires exit the gear case. There is just the wire guard and the wire retainer to hold the wires in place behind the guard. (that's the wires for forward and reverse electro magnets in gear case). The retainer in not big enough to block the hole.

In the housing sectoin jus above the gear case, there is a 'weep' hole for water to drain out when I put the boat onto the trailer. It just kinda drips out of the weep hole which I understand is normal, however, my thoughts are: if water can get out, then water can get in too, and whats to stop the wtaer from going into the hole for the wires and getting into the gear case??

I am really hoping that I can get someone on this forum that knows about the electric shift motor and specifically of the problem I have run into here. It seems that the hole need to be sealed in some way, but yet, there was no seal at the location when I started the tear down. But, at the same time, there was water in the gear case and maybe that's why?? The motor again, is a '62 Evinrude, 40 h.p. Mod. # 35933 electric shift.
Thank for your knowledge on this! IGGY

Re: my leak in lower unit

Durnit! Sometime I wish hindsight would hurry the hell up!

The thought struck that if you had the lower unit off... THAT would be the time to pump it full of lube - while you could watch the top.

Re: my leak in lower unit

Jim Geezer,

I am going to do just that today. I am removing the loewer unit again to check things out, as I certainly cannot use it the way it is right now, and I will fill it and see where the oil is coming out at from the gear box. 10 to 1 says it is coming from around the wires for the electro magnets, but then I still have to figure out how to seal them.
Thanks again.

Re: my leak in lower unit

OK Jim Geezer,

I took my lower unit off again and I found a mis-aligned 2 inch 'O' ring between the two parts of the engine where the seam was leaking lower unit oil. This 'O' ring encampasses the pinion gear and the wiring, completely seperating it from the space where the water bleeders are on the motor. The o-ring was not placed properly and that's why when I filled the lower unit with oil , the oil in turn came out of the bleeder hole.

I made an additional "rookie mistake" today when I took the lower unit off. I removed it and took the two parts apart right side up instead of upside down (I see it now in my manual where it states to turn it upside down so the bearings do not fall out), and all of the pinion gear roller bearings fell out. 5 of them went into the gear box when they came out. Had to take the gear box apart to get the fifth one out. Got 4 out ok, last one was lodged under the gears somehow. UGHHHHH! I have the roller bearings that go in one at a time, held in place by vasoline until the pinion gear is put in, not the kind in a bearing holder. I should be all set now (I hope).