Shifter won't engage forward or reverse

[Donut147]

1973 Cobalt 16'
165 hp Mercruiser inline 6
Mercruiser Sterndrive
S/N Engine 3557135
S/N Sterndrive 3567568

Each year when I put my boat in the water for the first time it typically will not stay running when I shift it into gear. I've learned to adjust the idle up a little and that always takes care of the problem. After a few minutes of driving I adjust the idle back to normal.

After three years of no use I got everything ready to go this year and was expecting this same scenerio. I actually had no opportunity to adjust the idle up this year, as I had no screwdriver in the boat. Expecting it was going to die, I shifted pretty swiftly into reverse (and because of a close proximity to other boats and docks) shifted quickly into forward and was surprised that a) it didn't die & b) it shifted much firmer than in past boating seasons. I decided to drive directly to my dock before I experimented anymore. When I got to my dock I shifted into nuetral, but from that point on I could not get the boat to go into forward or reverse.

After getting towed to my dock and the boat up on the lift my first impression was that when I tried to move the shifter into forward or reverse with the boat not running I encounteedr a much stiffer shift resistance than what seemed normal. That has since abated. Today I disconnected the lower shift cable and it seems that the shifting is fairly normal on both the lower and upper shift cables.

What seems worrisome is that I reconnected the shift cable and put the shifter in reverse wot and had my assistant spin the prop clockwise. It would not lock up. We then tried forward WOT and spun it counterclockwise and it would not lock up. Whether testing in forward or reverse we only got a heavy clicking sound and feel (2 or 3 heavy clicks per revolution). I was doing this test to check the shift cut out switch, I was suspecting it was not adjusted properly.

Thanks for any help I may get, sorry this was so long.

 

[Bt Doctur]

Re: Shifter won't engage forward or reverse

start by removing the drive and check everything for corrosion.Manually try the gears in the drive. Other than that it sounds like a bad lower shift cable.

 

[Donut147]

The Solution (or how to adjust a Pre-Alpha shift cable)

The Solution (or how to adjust a Pre-Alpha shift cable)

This is what we did to solve the problem (all adjustments were to the lower shift cable):

First we adjusted where the cable end guide mounts on the adjustable stud. Our cable was not in the lowest position on the adjustable stud so we started by lowering it to the lowest position (we were able to do this without pulling the cotter pin at the brass barrel, this saved time), shifting fully into reverse, then checked the prop to see if it would lock up in a clockwise rotation. It would not. We then repeated this process in small increments checking each time to see if the prop would lock up. Finally we reached a point above where the original setting for the adjustable nut was set, that caused the prop to lock up in reverse. We tightened the adjustable stud, but left the nut and washer off that keeps the end guide on the stud.

Next we removed the cotter pin that holds the brass barrel in position. We slipped the cable and brass barrel out of the holder. We had to use some wd40 to get the brass barrel to budge, but finally we were able to start making adjustments to the barrel. In our case we guessed that the correct direction to start adjusting the barrel was to the right, or turning it clockwise on the cable. We did this in increments of sometimes one complete turn, sometimes a half turn. Each time we'd place the barrel back into position, put the end guide back on the adjustable stud, shift the shifter into the far forward position, then check to see if the prop locks up by rotating in a counterclockwise direction. We also tested Reverse, to make sure we weren't losing it's ability to lock up. Eventually we completed enough turns on the brass barrel to cause the prop to lock up in Forward, we also tested Reverse and it was still locking up. All the while we were observing the firmness of clicks when ratcheting in the opposite direction in both Forward and Reverse. Reverse had a much firmer ratcheting feel and louder sound. We continued to adjust the brass barrel further, testing each time to see that we had not lost FWD or REV lock up, how the ratcheting felt in each direction and lastly the shift cut out switch's roller position. We were trying to adjust the brass barrel until the shift cut out switch's roller position was perfectly centered.

We were uncertain about how successful we were at centering the switch roller (it looked pretty centered) and decided to put the boat in the water and give it a test. It shifted into Reverse quite successfully. In Forward it would shift into gear and stay running if I shifted it slowly. If I shifted too quickly the motor would die.

That was all the time we had and were quite happy with the results (considering where we started from). When we get back to the lake we plan to continue adjusting the brass barrel in the same direction hoping that we can improve the Forward shift. In our boat it's very hard to see the Y bracket & shift cut out switch. We believe the cut out switch is the remaining issue and I'll report back after we are able to make further adjustments.

What we don't understand is how the shift cable, after years of working got so far out of adjustment. Is this normal? I hope someone knowledgeable about such things takes the time to read my first post describing the history of my boat's shifting issues and can speak to what would cause so much adjustment. I think we probably rotated the brass barrel 3 to 4 full turns to get us to the point where we had both FWD and REV. Also, does anyone understand the implications of the ratcheting of the prop, firmer & louder in REV than in FWD. Would further adjustment cause them to be more equal then they presently are?

Sorry this is so long and thanks to anyone who can answer those last questions.

 

[Bt Doctur]

Re: Shifter won't engage forward or reverse

you need a new shift cable.

 

[Donut147]

Re: Shifter won't engage forward or reverse

What has happened to cause me to need a new shift cable, obviously it's old. Do the symptoms indicate it's corroded, stretched, come loose or what?

Also, how much time do you think I have before the current fix doesn't work any longer?

Thanks for your help Bt Doctur.