Help separating upper & lower gearcase housings on 1987 Force 50

[chieftaing]

Clymers says that after removing the one nut in upper gearcase housing & the one nut in the lower gearcase housing (after pulling prop shaft bearing cage) you can separate the upper gearcase housing from the lower.

I'm replacing seals & want to separate the housings to make it easier to pull the shift rod & driveshaft seals.

I can pry apart the aft side of the housing, but the front seam between the housings wont budge. I've tried putting a nut on the bolt that sticks through the top housing & using various tools & deadblow hammer to split the housings, but I'm hitting pretty hard & there's no crack opening up on the front part of the seam.

Are the housings supposed to separate with just the two bolts removed like the Clymer book says? Suggestions on how to separate them without cracking the housing?

At some point do i give up & just replace what seals i can?

Thx

 

[Chrisravosa36]

Get a good manual...this will help alot, you will probably need it for the l.u anyways.

 

[Frank Acampora]

That was **** poor engineering and Force did not change it until Mercury/Force used the Mercury lower unit. NOW: The rear is held by the stud and nut inside the gear case and yes, you must remove the bearing carrier to access the nut. And, of course, the nut can only be turned by a small sized 9/16 open end wrench.

The front of the gear case is held by a really long stud with the nut outside the top of the lower unit. Remove this 9/16 nut and you can separate the gear case halves---YEAH, when the sun rises in the west. The problem is that moisture DOES get inside and the stud runs through a small diameter hole right through the full length of the upper section. It does corrode and the stud will (as in your case) be tight. Not much you can do here: Heat with a torch to try and break the corrosion or you can try running two nuts down if there are enough threads, locking them together and trying to twist it out.

Heat is the best option because the stud is so long that penetrating fluid simply will not penetrate far enough. Be gentle prying the two halves apart because later lower units ( and yours probably is one) have an O ring in a groove. Damage either half and you will need to replace it.

If you can work the gear case down about 1/8 inch this will free the pinion bearing from the upper half nest and you can then spin off the lower half. Of course this assumes that the drive shaft and shift rod are removed. Then you might be able to press out the stud

If you are lucky enough to get it apart coat the stud with anti-seize to prevent galvanic reaction between the steel stud and the aluminum case. It will make next time easier.

And Clymers is not a crap manual. Not as good as factory but no major errors either. I used to use it all the time

 

[tommarvin]

Free factory outboard service manuals at www boatinfo.no/lib/library.html

On home page left middle, click OTHER at the bottom for force and Chrysler find you're motor find your section and page.

 

[chieftaing]

Thanks Supreme Mariner Frank A! Just knowing its supposed to come apart is a huge help.

What do I heat? The stud? I understand the double nut & twisting it out.

I think I can get to all the seals without separating the housing, but its always good to have options! Thx again.

 

[Frank Acampora]

No, you need to heat the aluminum casting--aluminum expands a lot more than stainless and the hole gets larger. If you use a propane torch you may be heating for quite a while as this is a relatively massive piece of aluminum. A MAPP torch or acetylene if you can borrow one would be better. If you do use acetylene be careful to keep the flame moving and do not heat to the point of melting the aluminum.

Yes, if you are motivated enough all seals (except the O Ring or gasket between the halves) can be replaced without separating the halves.