Mercruiser Shift Problems

GKrzak

Recruit
Joined
Aug 4, 2008
Messages
2
:confused:

Hello all. I am having some problems with a Mercruiser motor. I have seen some threads that sound similar but I am not sure which one applies to my motor so I will post my problem.

The boat is a 1986 Mel-Hart Baretta with a 140 Mercruiser Motor. I would post the serial number but it is worn away on the motor. I have no idea what generation this Mercruiser is and we bought it used over 10 years ago. Worked flawlessy always. 3 years ago we needed to repair some of the vinyl on the panel that housed the shifter housing if thats what it is called (pardon my ignorance of proper terminology). We had taken the housing apart and quickly learned that we would be unable to put it back together (Lesson Learned). We took it to a local Marina and had them reassemble the housing. Unfortunately, due to other issues we were unable to get the boat back in the water until late last year (almost 3 years since repair) and we noticed some problems with shifting. With the motor running, the boat would go into forward or reverse just fine the first time. However, once you tried to shift from reverse to nuetral or forward to nuetral it would not go (For example pulling away from the dock). The lever almost seemed jammed. Occasionally, the lever would go into nuetral after fighting with it for a while but the motor would still be in forward or reverse. However, if you turned off the motor and restarted it it would start in nuetral. This made docking horrible. I would have to back out, kill the motor, restart to go forward. God forbid I had to turn around in a tight channel. Nightmare. Out of the water it shifts fine probably due to no load on the prop. I called the Marina that serviced it and of course they were no longer in business. Since then I have been trying to figure out what to do. I have taken it to many places to discuss possible solutions. One place lowered the idle a little and that made it better but the problem still exists. I think the idle is now at about 600-700 RPM's. At least now if going from forward to nuetral (or reverse to nuetral) it still resists but if I try a few times moving it back and forth it will finally pop into nuetral and stay in nuetral. Some places have told me it is the interrupt switch but the problem seems to have started after the dissambly of the control box. Maybe that is just coincidence. How do I test the interrupt switch? Are there any other possibilites? I think I have have seen the gear plate on the top of the motor. There is a pin that slides on what I can best describe as an upside down 'M' on the top (Again, excuse my ignorance of proper terms). When moving the lever back and forth you can see the gear sliding back and forth on the top part of the 'M'. It just has a hard time coming back after it locks into one side or the other. There are 2 cables that attach to this with barrels that spin and lock down to adjust the range of movement. I have had places adjust those as well and they say they are fine. This plate lies horizontally across the top on the front part of the motor. Next to that I think I see the interrupt with wires coming off of it. If that is correct, how do I test it? I think I have also read in other posts that if it is the interrupt switch it is no longer made so they have an adaptor plate you have to order. Does that apply to this motor? The only other information I can add to this to help right now is that the alternator belt the marina put on 3 years ago seems to bit a bit too long and has a lot of play. The belt slips and does not create the proper charging voltage so I have a constant voltage light. I plan on having this belt changed shortly with a proper belt to get the proper voltage flowing through the system. Could that have anything to do with it?

Desperate to solve this problem. If you have any suggestions or thoughts I am happy to hear from you. Located NW side of Chicago if anyone is local by chance.
 

knightowl

Petty Officer 2nd Class
Joined
Sep 20, 2008
Messages
111
Re: Mercruiser Shift Problems

haha my boat did the same thing... First time i took it out to water it ran only one way... If you shifted foraward you where stuck their no matter what. You had to kill the engine and once the engine restarted, you had to pick which way you wanted to shift next either forward or back.... I fixed that issuse by missing with my cable settings and mad sure it was to the books standers 6"
.



Now i can get all 3 of my gears to work but cant get the "smooth interrupter" switch to work with my shift timing... It just kills my engine everything i try to shift so right now i just disconnected it until i can figure it out. Heeelp?
 

freddyray21

Commander
Joined
Jun 10, 2006
Messages
2,460
Re: Mercruiser Shift Problems

most likely not the interupt switch, but the lower shift cable is binding causing the switch to not work. It needs replacing.
 

knightowl

Petty Officer 2nd Class
Joined
Sep 20, 2008
Messages
111
Re: Mercruiser Shift Problems

whats the cable have to do with it really? I mean if i have no problems shifting and i got it adjusted by the book and i have the arm move back/forth and the switch moves from the center of the arm to the edges back and forth, how is that the cables fault? Is the cable suppose to "un-trigger" the moving arm back into neutral zone magically? Just makes no sense to me. We know the interrupter switch also works because it kills the engine.

The manual didn't say anything about having it under water for the interrupter switch to work properly. Will the pressure force the cables to back-track the arm into neutral zone so the switch wouldn't be trigger any more? Just cant get the concept down. By fair the dumbest thing mercruiser could of ever engineered. Seems like everyone is having this problem..

Can it damage my outboard and gears if i just dont connect the interrupter switch since the whole shifting mechanism is a joke? I got a brand new engine with outboard installed. Thanks for replys fellas.
 
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