'59 Johnson 18HP Lower Unit questions

I am rebuilding the lower unit on a 1959 Johnson 18HP. It leaks water into the lower unit, I think thru the shift stem seal. While disassembling it, I noticed the end bearing on the gear shaft at the forward end 'looks' like it is cracked, but it could be intentional for oil passage or something. I also have questions about the dimples where some pin in the housing hits it. Is that normal?

Lastly, any hints about driving out the seals on the top of the lower unit where the driveshaft and gear select go thru? How about removing the seal on the prop shaft?

I wish I had an exploded view with the part numbers. I may have to break down and buy the parts catalog. Thanks for your help. I am learning a ton. I was able to get the carb rebuilt and the ignition parts all replaced. It runs great now, just need to keep gear oil in it!

Re: '59 Johnson 18HP Lower Unit questions

That's a crack. You need to replace it. And it looks pretty worn also. If you send me a pm with your email address I can send you the parts breakdown for the '58 Johnson 18 as they are very close and it's the only one i have.

And the pin is supposed to go in the dimple is to stop the bearing from rotating. Make sure they are lined up when re assembling.

Use a seal puller to get the seals out. As for the shifter bushing, search the forum and there will be instructions on how to remove the bushing to get to the seal. You need a 5/16" metal shaft taper ground down to 1/4" at end and you hammer it out.

Re: '59 Johnson 18HP Lower Unit questions

Thanks Samo, PM sent.

Well, I was hoping I was wrong. Everything you said makes sense. It looks like it was put together wrong, twice! That probably also explains why it leaked. I am going to shop around on eBay for another lower unit, it may end up cheaper in the long run as I also have a broken off bolt in this housing and a crack where the cavitation plate hit something. If anyone here has an extra in reasonable condition they would like to get out of the attic, let me know and I think we can quickly come to a fair price. I am reasonable.

Thanks again for the help!

Re: '59 Johnson 18HP Lower Unit questions

I got the manuel, thank you again for the help. Now that I know what it is called and have a part number for it, I may try to see if I can order one. It still may be cheaper to find an old lower unit if someone has one to get rid of.

Thanks again, this site makes everything much easier!

Re: '59 Johnson 18HP Lower Unit questions

If you plan on using the motor alot you might try Laings for a rebuilt lower unit. They are kind of pricey ($250) but tested and guarenteed not to leak. You could easily spend that much trying to source all the parts separately.

Re: '59 Johnson 18HP Lower Unit questions

Thanks for the information, I will check it out. I love old motors, but have just recently gotten the bug to work on outboards. My dad is loving it, he has a couple old Martins that he wants to get running again. Now that I am figuring out how they work, I have the confidence to do more with them.

The biggest problem I have is sourcing parts, and you have all been very helpful in that regard.

You are right, that is pricey, especially when you factor in the $115 I put into the top half on ignition parts, etc. and the $200 I put into redecking the pontoon boat it came with. More proof, there is no such thing as a free boat!

After looking at all the questionable junk on eBay, the $250 or so might be worth it. Thanks again.