1988 or 1991 155hp OMC Commercial Shift Shaft

[Mossbunker]

HELP!.. I decided to do "preventative" maintenance and replace the impeller on my 155 OMC. Problem is now that everything is reassembled, I cannot get the shift linkage to get all three gears. I started with the nominal setup dimension of 22 1/16 inch from Lower Unit to shift shaft hole center, but can only get reverse and neutral. I assumed shift shaft is too long so rotated clockwise 2 revolutions but could still only get reverse and neutral. Rotated clockwise 3 more revolutions and can get partial engaged in reverse, neutral is fine, and partially engaged in forward. Its like I don't have enough throw in my shift linkage to get all three gears, but I didn't dissasemble any cable/linkages other than the screw connecting the shift shaft to the shift linkage. I can manually shift into all three gears by pushing/pulling on the shift shaft if it isn't connected to the shift linkage so I'm pretty sure that lower unit, shift shaft, and gears etc. are OK... I'm out of ideas!!! Any help is greatly appreciated!!!

 

[ezeke]

Re: 1988 or 1991 155hp OMC Commercial Shift Shaft

Were you in neutral when you set the shift rod length? Did you measure to the center of the hole?

The easiest way to get the cable right is to disconnect it at the shift arm and get the gears working manually. Then adjust the cable to the shift arm following the manual for your engine.

 

[Mossbunker]

Re: 1988 or 1991 155hp OMC Commercial Shift Shaft

Thanks for the quick reply ezeke! I did measure with the shift shaft in neutral, but I didn't adjust any cables. I figured that since everything was working before I took it apart that as long as I set up the shift shaft length the same everything would work again without additional adjustment. The only other thing that I noticed is that there is a "seal" or some type of sealant inside the motor housing that the shift shaft passes by. My shift shaft is behind that seal and the seal seams to be stretched around the front of the shift shaft. This is preventing the shift shaft hole from lining up perfectly with the hole in the shift linkage, and I have to use a screwdriver to flex the shift shaft forward approximately 1/4 inch to get the holes to line up. I am wondering if the shift shaft is supposed to go through the sealant, or in front of it... I am thinking about seeing if I can move it forward, but I will have to drop the lower unit again to try it. Any suggestions would be great before I chase a bunch of guesses as to what the problem might be... I am hoping to get everything finished before tomorrow... I want to fish in the morning!... Thanks again!

 

[ezeke]

Re: 1988 or 1991 155hp OMC Commercial Shift Shaft

Assume you mean the gasket at the top of the midsection. It is soft rubber, round, flat and has a slit in it so it can be pulled around the shift rod.

Generally, after you get the gearcase in place and check the gears with the shift arm, you reconnect the cable something like this:

Move the control arm all the way forward and back to neutral;

Make sure that the warm up or fast idle lever is all of the way down;

Make sure that the gearcase is neutral and put the shift lever in the center of its free travel;

Connect the cable without replacing the trunnion and without moving the shift lever;

Adjust the trunnion until it will go into the anchor pocket without moving the shift lever.

 

[Mossbunker]

Re: 1988 or 1991 155hp OMC Commercial Shift Shaft

Nope... not that round slit "washer" that surrounds the shift shaft just before it enters the motor case. The seal that I am referring to is similar to body panel adhesive on a car... it looks like expanded foam, it runs around the seam and seals two mating portions of the motor case. It is kind of difficult to tell specifically since it is dark in there and there is quite a bit of oil on it. The shift shaft seems to protrude up into the motor case through this line of sealer, but in my case it looks like the sealer has been pushed forward (towards the bow) by the shift shaft. I am getting the impression from some other people that I have been asking that the shift shaft should line up with the the shift linkage in the fore/aft direction without my having to flex it forward (further stretching this sealant). I'm thinking that the sealant might be putting a bind in the shift shaft, but I guess I wont know until I try to move it... Thanks for all of the help! I will post a reply if I find the source of the problem.

 

[ezeke]

Re: 1988 or 1991 155hp OMC Commercial Shift Shaft

You could save yourself a lot of time if you would look up part names and motor section names in the parts diagrams for your motor before you ask the questions. You probably would get better answers as well:

http://epc.brp.com/default.aspx?brands=ej&lang=e

BTW, When you measure, the shift rod offset should be facing forward and the measurement is from the mating edge of the gearcase.