push button shift on Merc trans
 

Hello everyone, i'm new on the forum.......i recently bought a 78 scarab 300. It has the old electric shift trans in it. (they work good at the moment) The boat still has the god awful looking morse chrome shifters in it which has the micro switches inside of it for the electric shift.

My question is could i put livorsi throttles to work the throttle cables and put the electric shifts on 3 way rocker switchs on the dash. I know i would have to elimnate the neutral safety switch which i'm ok with..... another question is when the trannys shift in to gear, is it a constant 12v to the trans or just a momentary 12v? All your thoughts and info are greatly appeciated. thanks joe

You can swap them over to a regular set up that is not electric if you want.

Yeah, i gave that some thought but now i have purchased livorsi throttles that only have 2 throttle sticks and no drive levers. So i guess i'm stuck on this electric shift which i dont have no complaints about because right now they are working good, its just the original morse throttles is terrible looking and the cables are getting tight so i figured now would be the time to update the throttles. Do you think this could be done the way i mentioned in my first post with the rocker switches?

The normal setup supplies a constant 12 for each position, F, N, R. However once the drive motor reaches the proper position the switches on the motor itself kills the power. So I think momentary would work as long as you hold it down long enough to complete the shift. I don't think a rocker will work unless you do a circuit with relays to provide the neutral signal. Easiest way would be 3 buttons.

so your thinking use a momentary push button for each function of the drive. One button for forward....2nd button for neutral.....3rd button for rev. And you think i would have to hold the button down for like 2 seconds until it completes the shift? thanks for the great Info!!!!!!!!

Does anyone have or know where to find a wiring diagram for the morse shifters with the electronic shift?

Electric Merctrans shift motors are problematic. It was a poor switch mechanism to start with, and Mercruiser tried to improve the design with a retrofit switch head in later production but even that effort was not successful. Fact is; complete failure of a shift motor only necessitated replacement, but in a majority of situations "partial" throw or "oscillation" restricted alignment with the control valve oil passages, which in turn, reduced oil volume under load. Result; clutch failure. The Merctrans is reliable under extremely high horsepower but any restriction in flow. pressure or cooling can invite mechanical failure. The only real solution towards longevity and reliability is conversion to mechanical shift.

does any one else have input on this or did any of you guys ever hear of any one doing this before?

theres a good reason they only used for a short time....

Yes, I agree 100% the electric shift was not very reliable. At least the micro switch type is much better than the early ones. I don't think the mechanical shift ever made it to the production engines. It was available from race division if I remember correctly.