shifting trouble

[trev_614]

I have a 1978 Mercury 150 that I have been working on for a while. I've had the foot off for a few weeks while I was working on other parts of the motor and I finally got around to putting it back on today and I found that it will no longer shift at all. It is stuck in reverse. The shift shaft turns but it never actually shifts. Can anyone tell me what might be wrong? Man I hope I don't wind up having that foot rebuilt.

 

[DHPMARINE]

Re: shifting trouble

Time for a manual.The lower unit and the engine HAVE to be in the same gear upon installation.I doubt you've hurt anything,but the manual will help you co-ordinate the two.<br />OOPS did I say factory manual?<br />DHP

 

[andrewkafp]

Re: shifting trouble

Does it have Power tilt or manual ?

 

[trev_614]

Re: shifting trouble

It has power trim.

 

[schaiss]

Re: shifting trouble

Trev, DHP is correct. The LU must be reinstalled with the control in the position it was in when you took the LU off. I know this may seem time consuming (and a little bit of work) but the gears are out of synch with your control. When you replaced the LU was the engine in FWD, REV or N ? Disconnect the + lead on your battery! Pull the LU and place the control into a different position and pull the LU back into place (do not tighten the bolts)! With the shifter in FWD you should be able to turn the flywheel by hand in one direction (and not the other). With the shifter in REV you should be able to turn the flywheel by hand in opposite direction (and not the other). If you keep track of which position the shifter is in each time you should have it right on the second try !

 

[trev_614]

Re: shifting trouble

I know that they have to be lined up when they go together. The problem is, even with the lower unit off, the shift shaft just turns and does not shift. With the lower unit on, the shifting cable goes into each position, and the shift shaft turns, but it does not shift. I'm thinking that the shift shaft may have slipped out of the shift cam or maybe something slipped out of place by it being moved around.

 

[johnrob]

Re: shifting trouble

Does the shift shaft rotate freely (can you turn it with your fingers only)? If you can then it has probably disengaged from the shift cam inside the gearbox. You will also find you can pull the shift shaft up and out of the gearbox. There should be a small R clip on the shaft inside the gearbox which prevents the shaft from being withdrawn. The clip can become detached especially if force is used to remove the lower unit and the shift shaft is 'stuck' in the leg connector.<br /><br />It is possible to re-engage the cam (if a little fiddly). You need to remove the shift shaft bushing and drain the lower unit. Then place the l/u on a bench resting on the back edge (the opposite edge to the prop). Looking down the shift hole using a torch, you should see the cam - jiggle the l/u until the seratted hole in the cam is clearly visible - you should then be able to poke the shaft back into the cam then replace the shift bushing over the shaft. If the R clip is missing get a new one before installing the shaft.

 

[Fishin4fun]

Re: shifting trouble

I ran into this exact same problem when I was working on mine 2 weekends ago. You have to VERY slowly turn the gear thingy <technical term> that engages neu, fwd or rev on the foot, there is a tool for it so that you dont ruin the splines on it. Just a very slight adjustment will make it. First turn it all the way one direction, then the other direction, noting how many turns or how much turn is able to be made. Split the difference between it, for example if it will turn 1 rotation in either direction, turn it to 1/2 turn and this will be your starting point for finding Neutral. Once you find neutral, make sure your gear shift is in neutral, and then she will go back together, not really easy but this is how I had to do her. THe special tool ran 13.95 at my merc dealer and it was way easier than my pliers with a rag. The tool is designed for this exact purpose. I think on your motors foot that there is only a 30degree movement from fwd. neu and rev. not a whole lot of movement either when you look at how much 30 degrees is. The shift shaft will most likely rotate further than that, thus the process described above.

 

[trev_614]

Re: shifting trouble

I want to thank everyone who helped me out. I finaly got it worked out and its shifting like a champ now. You guys were great and I am very grateful for all of your help.