1987 Force 50 Lower Unit Rebuild

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ryguy32789

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Hey All,

I've got a major lower unit oil leak coming from the water intake, so I'm fairly certain either my driveshaft seal or shift rod seal are shot. I've already got the complete lower end new seal kit from iboats and have the lower unit removed from the outboard. I can't find anything online that shows how to replace these seals - do I need to remove both the driveshaft and the shift rod from the gearbox? I can't tell from the parts fiche I've found, and all the links to service manuals go to the now-defunct Rapidshare. Any advice or help is greatly appreciated.
 

jerryjerry05

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Usually a repair shop has the special tools to remove and install these seals.
But I doubt you can find someone with any special tools.
So use a punch/drift, sockets and be very careful to not score any mating surfaces.
Use sealer on the seals.
Pay attention on how the seals come out as putting them in backwards will cause a leak.
Pics will help.
 

Frank Acampora

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The drive shaft seal can be replaced by removing the water pump and the drive shaft. The drive shaft just slips out and there is no need to worry. the pinion on that lower unit should not slip out of position so the shaft should be able to slip right back in through the new seal. Use a large screwdriver to pry out the old seal. Use something flat to drive the new seal home. be certain to start it straight or you will ruin it. Light taps until it is started well. Lightly lubricate the drive shaft and don't let the splines damage the new seal when you put it back.

The shift r is removed by removing the shift rod. then screw in n appropriately sized lag screw and pull it out. Drive in the new seal metal side up. do not drive it home until the shift rod is in place. Then use an equal sized socket and piece of pipe to drive it in. The seal should not be too tight. The shift rod should not be loose but should move with a small amount of drag to ensure sealing.
 

ryguy32789

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Thanks so much, this is exactly the kind of info I am looking for. As for the driveshaft - I can pick up the entire lower unit with it, it doesn't seem to want to come out. Do I just need to put some muscle behind it? I don't want to break anything in the gear box pulling on something I shouldn't be.
 

ryguy32789

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Also, how is the shift rod removed from the lower unit? Does it have to be opened up?
 

jerryjerry05

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The shift rod, it unscrews.
Just make sure you don't move anything when the rods out.
The parts can move and fall out of alignment.
Then you'll need to dismantle.
 

Frank Acampora

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Unless you remove the water pump and impeller, it will hold the drive shaft in place then, some may be tight and you need to pull hard. The shift rod unscrews and undoubtedly the piece it screws into will move. It screws into a square pivot block on the shift yoke. So, unless you are very careful or lucky you will need to fish around when you put it back
 

ryguy32789

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Thanks for the input. I'm thinking it might be possible to hold the lower unit upside down when screwing the shift rod back in so that the pivot block is hanging in the correct orientation.
 

chieftaing

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Hey ryguy - did you replace any other seals or o-rings?

My 87 Force 50 has very milky gear oil after a summer of fairly light use so I figure I need a seal kit and replace as much as I can. I can see the drive shaft and shifter seal replacement, but I worry about how to replace the seals on the prop shaft - my Clymers shows a seal and an O-ring - requiring a tool to pull the bearing cup. Did you tackle that? Any pointers?

Thanks.
 

jerryjerry05

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Chief. The OP posted this in July and hasn't been back since.
You should try posting yourself.

Before you start tearing it down do a pressure test.
Lots of times the seals on the drain and fill leak and cause the problem.

Yesterday was working on a 15Yam. Impeller was bad.
Part of the service was changing gear oil etc.
I opened the drain plug and water came out.
Only water and no oil. Hope it didn't wipe out anything.
Turns out after a pressure test the drain plugs hadn't been tight enough.

Save yourself some trouble and get a factory manual.
Clymer is marginal.

 

chieftaing

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Im on the same journey. Learned that removing the prop shaft bearing guide is possible without puller by removing screws, then tapping lightly on ears to rotate guide ears to the point when they can be *lightly* tapped one after the other to push it out. Worked for me.
 

tommarvin

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Nov 22, 2015
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Free factory service manuals at www boatinfo.no/lib/library.html

On the home page left middle click other at bottom for Force and Chrysler . Find your motor..
 
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