OMC Stern Drive 400 Help

shanman41

Recruit
Joined
Aug 20, 2017
Messages
3
Hello Everyone,

I am new to this site and boating in general. I am working on an engine swap with a OMC 120 with a stern drive 400. I pulled the outdrive off and the motor and intermediate housing are out of the boat, but I having hard time separating the two. I have pulled all the bolts that mount the bell housing to the engine, but I can't get them to separate. I am only getting it back about 1/4 inch. I am thinking the splines that go into the flywheel are stuck.

Any advise how to get them to release? Any help would be much appreciated.
 

kenny nunez

Captain
Joined
Jun 20, 2017
Messages
3,056
Try removing the bolts that hold the intermediate shaft flange and with a suitable slide hammer maybe that will pull the shaft. If that does not work this is the only way without destroying everything and it is going to get messy.
Drain the oil from the engine. Lay the assembly on it's side. You will need to cut an access slot in the bottom of the adapter housing close to the flywheel where you will be able to loosen the 6 bolts that hold the drive flange to the flywheel, you will have to turn each bolt a little at a time and rotate the engine to the next bolt, it is very tedious and a real PITA but it can be done with patience.
 

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
Kenny is spot on. It is undoubtedly rust holding the intermediate shaft into the flywheel coupler. There is an o-ring inside the opening of the coupler that is supposed to hold the grease on the splined shaft, inside the coupler. That grease dries out and moisture does its evil work. Too bad there is not an access hole in the bell housing that you could use to saturate the shaft opening.to the coupler with penitrant.
 

shanman41

Recruit
Joined
Aug 20, 2017
Messages
3
Thank you so much!

How do you purpose connecting the slide hammer to the ball gear to pull the shaft out?
 

kenny nunez

Captain
Joined
Jun 20, 2017
Messages
3,056
You may be able to rent one, they can be configured in either 2 or 3 finger styles.
If you still cannot remove the shaft then you will have to cut the access hole in the bottom of the adapter housing. If you have an acetelyene torch try heating the coupler on the flywheel and and using the slide hammer. If you do it that way re bolt the housing to the engine first.
If that does not work then you will have to work the bolts out as I described before and while backing the bolts off wedge some screwdrivers between the engine and adapter housing to keep a pulling force .
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Jul 23, 2011
Messages
47,300
Thank you so much!

How do you purpose connecting the slide hammer to the ball gear to pull the shaft out?

I normally weld a plate on the ball gear with a nut in the middle to attach my 30# slide hammer (yeah, its a big-one). the gear is shot anyway
 

shanman41

Recruit
Joined
Aug 20, 2017
Messages
3
Thank you everyone for your help. The slide hammer method worked and I was able to get the bell housing separated from the block. I now have the engine sitting on the stand.

I am sure I will have more questions as I dive into this more over the course of the winter, but thanks again for everyone's help. :)
 
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