1972 50hp Evinrude shift question

[dogpaddlin]

I have a 1972 model Evinrude electric shift (model # 50173 S) that stays in gear (forward) even with no switch wired in. Is this common? The push buttons were sticking and I wanted to replace them with a toggle. Can I not do this? Does someone have a wiring diagram for the shifter?

Thanks in advance.

 

[Barnacle_Bill]

Re: 1972 50hp Evinrude shift question

With no power applied it will be in fwd gear.

 

[Barnacle_Bill]

Re: 1972 50hp Evinrude shift question

I take that back. I believe that motor is manual shift and not electric. My manual is somewhat fuzzy on that. Can someone verify?

OK, I got it straight. Electric start does have electric shift. I know of people that have used a toggle switch so it can be done. You have 2 wires going to the shift solenoids. A blue and a green. In fwd gear there is no voltage on either wire. In neutral there should be voltage on the green wire only. In reverse there should be voltage on both the green and blue wires.

 

[jay_merrill]

Re: 1972 50hp Evinrude shift question

1972 would make it a hydro-electric shift and that's exactly what it should do. When the motor is running and you have the shift handle in neutral, one solenoid in the gearcase will be activated, and via a hydraulic/piston system, the clutch dog is disengaged. When you move the handle to reverse, both solenoids are energized and the clutch dog is engaged in the reverse position.

If you use the search function here in the forums, you will find a few threads on dealing with NLA shift switches. That said, you might find a functional control unit on one of the auction sites.

If you do go to a toggle, you will have to use two in order to replicate the neutral safety feature in the starter circuit. You also have to be very careful with a shift toggle, so you don't inadvertantly shift into reverse with high rpm on the motor.

I don't have a wiring diagram for your motor, but here's one (below) for a 1972 65hp Johnson. The shift circuitry should be the same.

One "peculiarity" of the shift circuitry that you should be aware of is the "diode and lead assembly." While the keyswitch is in the on position, the neutral circuit is energized by the battery or rectifier. When you turn the keyswitch off to shut the engine down, the power comes from the diode and lead assembly. If not for this fact, your gearbox would shift into forward the second you turn the key off.

To find it on your motor, look for a small ball on the starboard side that is brown. It will be near the electrical distribution block.

Be aware, also, that you can't use the type of gear lube that most gearboxes require. The hydro-electric gear boxes use a thinner lube that serves as a hydraulic fluid too. It used to be called "Type C," but is now referred to by BRP as Premium Blend. Just ask your local BRP deal for Type C oil, or tell them the year of your motor, and they will give you the correct equivalent.

 

[tashasdaddy]

Re: 1972 50hp Evinrude shift question

two major discussion on it.

http://forums.iboats.com/showthread.php?t=175907&highlight=electric+shift+toggle+switch

http://forums.iboats.com/showthread.php?t=269622

additional info: Hydro Electric Shift)
(J. Reeves)

The shifting setup of the lower unit is what's called a "Hydro Electric Shift", which is quite complex consisting of voltage being applied to solenoids in the lower unit which in turn change oil passages via a oil pump that supplies various pressure on a spring loaded shifter dog. The wires leading to the lower unit (at the powerhead) are "Green" and "Blue". The engine must be running or cranking over in order to shift out of forward gear.

You CAN NOT use HI VIS lube in that lower unit. You MUST USE what OMC calls "Premium Blend" lube, commonly called "Type C". (A thinner lube)

In neutral, you need 12v to the "Green" wire.
In reverse, you need 12v to both wires, the "Green" one and the "Blue" one.
In forward, there should be no voltage to either wire. (The spring loaded shifter dog forces the unit into forward gear)

To check the lower unit for proper shifting to make sure you have no trouble there, remove the spark plugs to avoid problems and to allow a higher cranking speed.

This next step eliminates the actual shift switch in case problems may exist there.... Disconnect the blue & green wires at the knife connectors (the rubber insulated boots) leading to the lower unit at the powerhead, then using jumpers, take voltage direct from the starter solenoid to apply voltage to the "Green" wire for neutral, then both wires 'Green" & "Blue" for reverse (Remember the engine must be cranking over in order to shift).
With no voltage applied, the unit should be in forward. No need for a ground jumper... the lower unit's already grounded. You may crank the engine with the key switch or by energizing the starter solenoid with a jumper wire.