50 HP Johnson questios // new guy

[btroy]

Hi guys, I have an old 72 50hp Johnson and the lower unit is going out.

It has an electric shift. I took it to the shop but he said he would not touch it, as it has an electric shift.

The symptons are it will come out of gear under load. As in saying it will idle ok and perform ok when going slow but if I put it under load and attempt to go fast it is like I hit something. In 30 feet of water there is nothing to hit.

I have a parts motor and it is an electric shift also. What I would like to know are parts available of an electric shift to be repaired?

I am pretty mechnicaly inclined so I am sure I can fix it if parts are available. With a little help for you guys.

I am needing to get a manual so I will work on that this week. What I think I will do is rebuild the parts engine lower unit and then swap them out.

Another question for now. I assume it takes 90 weight gear lube in the lower unit. I attempted to change the fluid but it does not appear to be taking in fluid in the fill hole. What is the correct way to refill the lower unit with lube. When I drained to fluid it was black with no milky look to it so I would say no water is getting into the lower unit.

Thanks to all that input advice, any help I can get will be greatly appreciated.

 

[tashasdaddy]

Re: 50 HP Johnson questios // new guy

DO NTO USES 90 WT!!!

it takes only BRP Premium Blend Type C lower unit oil, for electric shifts. dealer item.

it sounds like the clutch dog is shot. as i will go into gear, which says the solenoid is shifting. this usually means replacing the clutch dog and forward gear. there mating surfaces have worn, to the point the will not stay engaged. i presently have a great 71 50 power head with a useless lower unit. do to a bad wiring harness to the lower solenoids.

these lower are tedious to work on. #1 the wires get damaged removing or replacing the unit. there are not any new harnesses. the solenoids are NLA.

new clutch dog is $120 forward gear $125, while there water pump kit $42.00, plus a lower unit seal kit.

Starting to get to the cost of about what the motor is worth. repaired.

 

[btroy]

Re: 50 HP Johnson questios // new guy

and how do I fill the lower unit?

Will the manual tell me what I need to know to fix the unit or should I just look for another good lower unit?

 

[tashasdaddy]

Re: 50 HP Johnson questios // new guy

here is more 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.