1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

I bought a 17' 1962 Red Fish boat that came with a 1962 Johnson 75hp outboard. I topped off the gear oil in the lower end and took it out for the first time this weekend. When I pulled the drain plug to check the oil today it was milky due to water being mixed in with the gear oil. My question is, on the port side of the engine there is a small, approximate 1/2'' hole that I can see through. (It's the 3rd section up from the prop housing. With the prop housing being #1) Through the hole is a silver metal shaft which runs downward towards the prop housing. Is there supposed to be a plug in this hole? It did not have one when I bought the boat. My guess is that there is supposed to be a plug in that hole and that is where the water is coming into the gear case. Yes or no? Any help would be great. Thanks!!

-Dave-

Re: 1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

Some picts would be helpful. But from my experience it is usually the prop-shaft seal. Have you taken off the prop yet? You may find fishing line or even rope behind it. This will cut into the prop-shaft seal. But I have seen people take out the drain vent plug and forget to put them back in. So a good Pict. would help.

Re: 1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

I don't think that is your problem. I would drain the gearcase and install new seal washers on the fill/vent screws and refill the gearcase and run it and then check the oil again. If you are still getting water into the gearcase it will probably have to come off and get resealed.

Re: 1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

Wow. Thanks for the quick reply. I did, in fact, have the prop off. Nothing back there. I'm working on the pic now. It is the hole directly below the bungee cord.

Re: 1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

I added a picture to my previous reply.

Re: 1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

Kinda hard to see, but I believe that is a drain hole. What you are seeing on the inside of the hole is the outside of the casting where the driveshaft runs down through the lower unit. I could be wrong though, since I can't see the hole so well in your pic. I'll have more time later and I'll post some pics of what my lower unit looks like around that drain hole. In the meantime, can you post a closer shot of that hole?

Re: 1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

here is a closer pic of the hole.

Re: 1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

That engine has a 5" exstension. This exstension is just a hollow casting that take's the engine from 15" to 20" I think you are looking at a drain hole to keep this part from freeze cracking. You have oil fill gaskets, prop shaft, drive shaft, and shift rod seals. The two long studs that hold the lower gear case on have seals at the bottom end. An engine this age could be leaking anywhere.There is also a large o-ring between the gear case halves

Re: 1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

Yeah, that's definitely your drain hole. I'm worried about the "silver metal shaft which runs downward towards the prop housing" though. Again, there is a cast-in tube that surrounds the driveshaft and prevents exhaust gases from passing up to the motor. You should be able to see the protective tube while looking into that drain hole, but you should definitely not be able to see the driveshaft itself. Have somebody turn the motor over by hand and look to see if the "silver metal shaft which runs downward towards the prop housing" rotates. If so, it is the driveshaft that you are looking at and you'll need to get a new extension. Let us know what you find. By the way, no matter what is wrong with that part of the motor, it will not lead to water in your gearcase. The gearcase is a completely sealed unit that mounts to the bottom of the extension. Even when you take the gearcase off, it should still be a sealed unit.

Re: 1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

Can't tell but is the hole threaded?

Re: 1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

Thanks for all the info guys. Very helpful! I'd have to agree that it's just a drain hole. I'd bet that my lower unit needs resealed. I'm a diesel mechanic by trade so I'm very mechanically inclined. Is removing the lower units and resealing them something that's fairly simple if you know what you are doing? Or does it require special tools, adjustments, etc? Would I need to pick up a manual or something or could I just take it apart and tackle the job? It looks like I'll have a winter project. Thanks again.

Re: 1962 75 hp Johnson Outboard...water in gear oil. I have an idea....Am I right?

Best to pick up a Factory Service Manual from ebay or from the Ken Cook Company at outboardbooks.com though you could tackle it by yourself by searching through threads on this forum to get all of the details. The FSM would be easier.

There are no special tools that I can think of, though you'll need to rig a puller for the gearcase head (aka prop bearing carrier). You can find the exploded view of your motor at marineengine.com as well. I have the electric shift model so I don't know the ins and outs of disconnecting the mechanical shift components when removing the LU. The FSM will list all of the steps in detail. If you have mechanical shift, there are certain screws on the shift linkage that should be removed and certain screws that should be left alone.