Water in Oil 1957 Johnson AD-11 7.5HP

[57johnson]

I am in the advanced stages of disassembly of a 1957 Johnson AD-11 7.5HP. This is my first ever attempt at working on an outboard engine. I am brand new to your organization so go easy on the "newbie"!!! 🙂
So far I’ve been very fortunate and have only found a bent shift rod along with the normal maintenance items. As I’m a newbie, I’m waiting on a flywheel puller so I can look at the magneto components. But, through the inspection port they look "like new".
One item that I noticed was when I drained the oil from the gear case. The first 1 ounce was clear water followed by aprx. 8 ounces of oil. I understand that water will sometimes work its way in due to worn components. My question is do I suspect the seal on the prop shaft, the seal on the drive shaft(by the water pump), both, or something I’m not considering.
Also, any info on replacing either of those seals would be appreciated.I see there was a special tool (301927) to pull the drive shaft seal (300599) but it does not appear to be available.
The prop shaft seal "seems" like it should slide off the prop end but it, and the gear case head and bearing assembly, seem to get stuck right near the end of the shaft where the shear pin and cotter pin holes are. It doesn’t seem rough there, but then again I’m new at this.

[reivertom]

First thing……Don’t take the lower unit apart without photographing every thing as you go. The first time I rebuilt one with new seals, etc., I laid everything out exactly like the parts were together in order, and I took photos so if I had problems I could see the order they went back together and which direction they faced. It saved me from screwing up and it worked perfect when I re-assembled it. The string seal (spaghetti seal) between the clamshell halves is a bit tricky, and if you search around you can find info that will help you. You will need the proper sealant for this part also. There are different ways to replace the shaft seal, but a dedicated tool seems to work best for most folks. I have read about making a tool on here someplace, but I can’t remember where.

[Anonymous]

quote 57johnson:

My question is do I suspect the seal on the prop shaft, the seal on the drive shaft(by the water pump), both, or something I’m not considering.

There’s also an o-ring on the shift rod.

[jerry-ahrens]

First off, welcome to the club, and to the forum! Those engines will run like a sewing machine once serviced.The shift rod seal is usually the culprit. I’ll bet if you replace that, you can probably leave the others alone. Of course replace the spaghetti seal on the gearcase halves. The shift rod o ring will leak on just about everyone of these old OMC motors if they are still original.

[crosbyman]

as a former mostly newbie and less newbie today all I can say is don’t be to worried about progressing into the lower gearcase Utube has excellent videos (attached) to help you along

the bible is also included in the links . there are various methods to
pull the shift rod seal but mine was the one using a piece of threaded shaft and wood block

have fun and if you are stuck anywhere just ask

http://boatinfo.no/lib/johnson/manuals/ … on.html#/0
http://www.youtube.com/watch?v=tA0u62hciwY
http://www.youtube.com/watch?v=EY2HrEdp5vg
http://www.youtube.com/watch?v=SVOedhzPP7M
https://www.bing.com/videos/search?q=ut … &FORM=VIRE
https://www.bing.com/videos/search?q=ut … ORM=VDRVRV

vintageoutboard.com has gearcase seal kits

Joining AOMCI has priviledges 🙂

[fleetwin]

Well, to be honest, these "clam shell" type gearcases are a challenge to get sealed properly….Trying to pull those seals out can be tricky as well, it is very easy to damage the castings the seals are in. You will need a special tool for removing the shift rod bushing to access the shift rod oring.
I would watch all the videos posted, then gather up the tools you will need and ask questions…
The best way to start this project is to figure out where the leaks are before ripping the gearcase apart. Simply replacing seals and orings does not guarantee the case will seal properly, there might be casting flaws, or grooves in the shafts. The best procedure is to pressure test the gearcase once it is removed from the exhaust housing. While pressurized at about 5PSI, submerging it into a bucket of water while rotating that shafts, and moving the shift rod will help isolate problem areas….

[jerry-ahrens]

Here’s another important thing to replace, once you have the powerhead off… #s 1 and 3 in the diagram. One is the cork seal and the other is the O-ring. be sure to reassemble in the correct order. Failure to replace these seals could result in a blown powerhead.. from water ingestion. http://www.marineengine.com/parts/johns … =Gear+Case

[Doug Wilson]

As others have said very likely the water is coming in last the shift shaft. When you put it back together make sure all of the seal parts for the lower crank shaft seal are there many times they are missing

Doug

how is it motors multiply when the garage lights get
turned off?

[57johnson]

Thank you for all the responses. I have the original paper 10th edition Johnson Service manual, the original 3rd Edition paper Service Manual, and the original paper part schematics for all engines I’m working on (thanks to an advertisement on your website).
I have what I consider a pristine motor. No parts missing. as you can see.
A further question is how to get the oil seal (300599) out of the drive shaft housing. I can not seem to find the special tool.
Also, as I put this back together Do you "dress" the various gaskets with anything?
Also, the various screws…….should I use some type of Loctite?

[fleetwin]

So, does this mean the gearcase is already apart?

[Author]

Posts