Johnson 50hp questions new to boats

[Seasprite71]

I recently purchased a 1971 Seasprite with a 1972 Johnson 50 hp electric shift. Long story short purchased boat last owner said he would bring me the complete lower unit I recieved a 500 piece outdrive puzzle. The prvious owner said last time he used the boat he put the motor into reverse and it got stuck in reverse he played with it and got it back into foreward so he took the boat home pulled the outdrive and took it apart. Here comes my question I found a 1972 50 Hp Johnson for sale with a bad piston can I use this outdrive and put my electric shift mech in it or can I put my power head on this motor and convert to an electric shift the motors look the same but I didnt know what problems there may be any help would be greatly appreciated Keith
The other motor is a cable shift and outdrive is good

 

[tashasdaddy]

Re: Johnson 50hp questions new to boats

motor are identical, as long as they are both the same shaft length. you can pick the best of both motors. both motors are hydro-electric shift.

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.