Shift Shaft removed, now can't get back into gear

[Buckeyebowhunter35]

Hello, this is my first post on this forum, trying to help a friend in need with his 1991 mercury 75 horse. We may have opened a huge can of worms and looking for advice.

So anyways here goes. My buddy was having trouble getting his new to him outboard into reverse and apparently had just changed the impeller. So he decided to remove lower unit to see what the problem was. One thing led to another and another friend of ours decided well there must be an issue with the shift shaft and proceeded to remove the shift shaft from the lower unit. My ignorance on the subject led me to believe there was no harm no foul. However the shift shaft no turns but rather spins freely.

Now the problem of getting the motor into reverse is overshadowed by not having a shift shaft in the lower unit.
Any advice would be appreciated!

 

[racerone]

Well------What happened is that likely the lower unit was removed in NEUTRAL.-----It then jumped into forward ( spring loaded clutch dog ) while being worked on.---Then on assembly it was in forward while control was in neutral.-----Correct on my assumption ?-----So now you need to fit the shift rod back into the shift cam.----Some disassembly and re-assembly may be required.

 

[Buckeyebowhunter35]

Well------What happened is that likely the lower unit was removed in NEUTRAL.-----It then jumped into forward ( spring loaded clutch dog ) while being worked on.---Then on assembly it was in forward while control was in neutral.-----Correct on my assumption ?-----So now you need to fit the shift rod back into the shift cam.----Some disassembly and re-assembly may be required.

Thank you for the reply sir. I am uncertain as to whether or not he was in neutral when lower unit was removed. However, I do know that the LU was in forward once removed as the prop would only spin clock wise. And he was having trouble getting shift shaft back into neutral or reverse for that matter. I do not know what led to the assumption that removing the shift shaft would solve something. But I am uncertain where to proceed from here with my advice for him. When you say disassembly what are you referring to? Thank you

 

[Buckeyebowhunter35]

My friend and I are pretty green in the LU department if that isn't apparent lol.

 

[Mark ofs]

There are lots of videos on Youtube that cover removal of the lower unit/impeller replacement, might be able to get some tips there with a search. Also, might want to invest in a motor specific service manual

 

[Buckeyebowhunter35]

The service manual I bought (seloc) shows nothing on actually repairing a lower unit. Garbage. We are trying to figure out how to get that shift shaft back into the shift cam without having to take the gear box apart. Is it possible? Have not had a chance to work on it since Tues. Thanks for the replies

 

[Mark ofs]

That’s strange….mine show's complete take down/repair…While these most likely are not the same as yours, here's a couple of pictures that might help you figure out what may need to be done...

 

[Buckeyebowhunter35]

Thank you sir. The research I have done for his motor shows a shift cam between two horizontal pylon type fixtures in the actual lower unit. I believe we have to somehow get that shift shaft lined back up with it. Although there are no YouTube or instructional diagrams on this maneuver that I have seen so far.

 

[Faztbullet]

You have to remove the carrier and propshaft to reinstall cam

 

[Buckeyebowhunter35]

You have to remove the carrier and propshaft to reinstall cam

Thank you for posting. This is the diagram I have seen and understand that we may have to remove the carrier. However what is preventing us from being able to reinsert without removing carrier if that Cam is just sitting there between those pylons?

 

[racerone]

Have you drained the oil to be able to see where / how the shift rod fits down there ?----And you are aware that the follower pin is pushed by a strong spring ?

 

[Buckeyebowhunter35]

Racerone, we're headed that direction this evening. No idea what the follower pin or spring is that you refer to. I have talked to a few marine mechanics and they have said it is possible to get it back in without removing the carrier but not easy. I really didn't want to have to remove the carrier or take it somewhere but that might be the direction we're headed.

 

[Buckeyebowhunter35]

Truly appreciate everyone who has responded. Not always easy to find stuff for these older out boards.

 

[racerone]

In many areas a 1991 motor would not be considered old.------And for many years these motors were built the same.-----Hurry and find what the working bits inside look like.------mercruiserparts.com------Have your serial # and click away.

 

[Buckeyebowhunter35]

Thank you sir! I guess shouldn't say old but rather "seasoned" would have been a better term. Will update after tonight's session.

 

[racerone]

If you can see where the shift rod goes it might help to put a big shamfer of the end of the shift rod to help in re-alignment.

 

[ahicks]

I made this same move not too long ago, and I know better. I was not happy.....

The first time I did this, I pulled it all down. The second time I couldn't get the bearing carrier to budge, so I ended up messing with it long enough to come up with a way to fix it - without pulling it down.

If (when) the shift shaft is lifted up, the cam drops off the end of it, and the cam slides back into a cavity, making it near impossible to reinstall the shaft into the cam. You need to reach WAY down inside the case to line up the cam on the opening, then reinsert the shaft and turn it to the neutral position for reassembly.

The key issue is how to get that cam lined up on the hole.

You WILL have to drain the oil from the lower unit.

My fix involved a long 18-24" fairly stiff piece if 10ga electrical wire. Set the lower unit on the bench with the prop shaft pointing down. This SHOULD allow the cam to drop into view, and allow the long piece of wire to be inserted into the hole in the cam. Once that is accomplished, stand the lower unit upright while leaving the wire in the cam (to keep it from falling to the front again). With the lower unit standing upright, you can use the wire to center the cam in the opening, remove the wire, and CAREFULLY drop the shift shaft down into place, engaging the cam.

There is no chamfering of the shaft required, as they come with all you need.

You may have to run through this process a couple of times to be successful.

Once the shaft is engaged, you can put the cap back on to lock the shaft in place, and turn the shaft to engage neutral for reassembly.

I know this lower as a Honda unit used on the '97 and '98 75 and 90 hp 4 strokes.

You can see the cam and the shaft as #10 and #11 here-
https://www.boats.net/catalog/honda...1-to-bbal-2999999/water-pump-vertical-shaft-1

Noteworthy is the fact this wonderful design was changed, along with a bunch of other changes in '99 or so - in the Honda line up anyway.

Best of luck! -Al

 

[Buckeyebowhunter35]

PROBLEM SOLVED!
Al, while I had not seen your post until now this is precisely what we did and it worked perfectly. After draining the oil we were able to use a strong flashlight to see down into the LU and see the shift cam just sort of floating around down there. Once we saw the hole somewhat lined up we were able to use a coat hanger to hold it in place while we gently tilted the LU back to horizontal and reinstall shift shaft. I ended up buying one if of the shift shaft wrenches off Amazon for like 15 bucks. Nice little tool, probably not going to use often but worth it when you need it. Thank you Al for the lengthy post and to others who tried to help. Pic for shits and giggles.

 

[ahicks]

Good job!

I would note for anyone following later that the wrench is fine, but not really necessary. There's not that much torque required to turn that shaft. If you're careful not to bugger up the splines, pliers will work fine for what needs to be done. FWIW, -Al

 

[Buckeyebowhunter35]

Al is 100% correct. No need for the wrench but for 15 bucks from Amazon prime I figured what the hell. It's a lot more convenient then using pliers and I'll have it case anyone I know runs into the same issue. Thanks again to all who replied.