1976 Chrysler 120 HP outboard Lower Unit Seal Problem

bassboy416

Petty Officer 3rd Class
Joined
Jul 9, 2013
Messages
79
I recently purchased a 1975 Tahiti with a 1976 Chrysler 120 Outboard Model 1209HD. It started and ran great but I only saw it run on a hose attachment. Once I bought it, the first thing I did was run it in a bucket of water to see if the impeller was in good shape. I removed the lower unit and checked the impeller and housing. All was looking good, and in a bucket of water, it did have water coming out of the tell tale pee hole thing; However, when I took it apart (and not before I took it apart) I noticed Milky Gear Oil coming out from the prop shaft area from what I believe to be the prop shaft housing (right behind the prop itself). I have read extensively about this, and I realize there is a very high likelihood this is in need of a lower end seal job. I drained the oil from the LU and it was not white but definitely had a milky color to it indicating water in the oil. It should be mentioned as well that the drain and vent screws were barely even hand tight and SUPER easy to loosen with a regular flathead and barely any pressure. I bought new washers for the screws and oil and was going to take it out once and then have seals redone, but the mechanics in this area said parts are unavailable and they will not work on the engine because it is obsolete. I have found seals for the lower unit, but I have never done this work before. Also, I tried taking out the two allen wrench screws holding what I believe to be the prop shaft cover in place and it would not budge. Couple of questions. Can I run it if I change the oil every outing? Can I find someone to fix it? Can I do it myself if I buy the manual and a slide hammer? If so, what gaskets get replaced? Your help is incredibly appreciated. I feel like I just bought a 19 foot lawn ornament. I'm going to try and paste the schematic of my engine I've found online for you to analyze. Thanks!!!!!
Boat engine.jpg
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: 1976 Chrysler 120 HP outboard Lower Unit Seal Problem

As you have already discovered, the seals are standard parts available at almost any bearing supply store. To remove the rear bearing carrier, remove the two allen head bolts. THEN, using a couple of pieces of all-thread 1/4 X 20 threaded rod, make a puller. There are two threaded holes either side of the prop shaft for this purpose.

NOW: the bearing carrier seals the lower unit with a large O-ring. the area before the O-ring will corrode and make pulling the carrier very difficult.

You can also try using a block of wood and VERY CAREFULLY tapping at the base of the bolt ears to spin the carrier so the ears are clear of the case. Then again, using a block of wood, alternately tap the ears to wiggle out the carrier. Anti- seize well when you reassemble.
 

bassboy416

Petty Officer 3rd Class
Joined
Jul 9, 2013
Messages
79
Re: 1976 Chrysler 120 HP outboard Lower Unit Seal Problem

You are 100% accurate in the description of what I've been looking at. There are 2 female threaded ends with no bolts in them that I've seen in what I believe you said is called the "carrier." Do you have any suggestion as to how I could fashion a puller with all thread? and when you say to use a piece of wood to carefully tap near the ears... what exactly does that mean. You really do seem to know exactly whats going on down there. Thank you so much for your help! If its just that O Ring, its like a 3 dollar fix.
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: 1976 Chrysler 120 HP outboard Lower Unit Seal Problem

Well, if you hammer a block of aluminum or steel against the bolt ears, you will bend them. SO using a block of hard wood hammer it near the base where the ears join the main casting. to fashion a puller, you take a block of something strong or a steering wheel puller may do. Slide the center hole over the shaft and threads but let it but against the splined portion. NOW Thread through the wings of the puller into the two holes a long piece of all thread. Run down two nuts and some heavy washers and start to tighten the nuts. They may pull out the bearing carrier or they may simply strip the holes. If they do strip the holes, simply tap to the next size up.

It is called the bearing carrier because it carries the "cup" for the rear tapered roller bearing. It is shimmed and sets the bearing clearance and shaft run-out in addition to carrying the rear seal.
 
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