1971 Evinrude 50 hp

[james28144]

I just had some engine work done on my 50 hp evinrude.
It had overheated and blew a head gasket and sat for 3 years.Motor is now running, but the transmission wont change from drive,neutral and reverse....it is a push button electric shift trans.
I removed the screw in the bottom of the lower unit and found there was no oil in it. Is there a sensor that will keep the trans from shifting if it is low in oil?? The motor seems to be locked in drive, since the prop spins as the motor is running.
If I turn off the motor and turn the prop manually, the flywheel will spin. I assume that the trans. is locked in gear.
It takes a special light weight oil for the foot because of the electric shift push button trans.

 

[Joe Reeves]

Re: 1971 Evinrude 50 hp

(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 "Preminum 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.

 

[F_R]

Re: 1971 Evinrude 50 hp

I removed the screw in the bottom of the lower unit and found there was no oil in it. Is there a sensor that will keep the trans from shifting if it is low in oil?? The motor seems to be locked in drive, since the prop spins as the motor is running.

You answered your own question. It cannot shift without oil in the lower unit. The unit is shifted hydraulically and the lube oil is the hydraulic fluid. It will always be in forward gear when not running or in case of failure of electical components or lack of oil.

If you fill it up and it still won't work, follow Joe's advice for troubleshooting method.

 

[james28144]

Re: 1971 Evinrude 50 hp

Thank You for your input on this. I will do as instructed and hopefully everything will work.