'69 55 hp Johnson hydro electic

[Leisure67]

I have a '69 55 hp Johnson with hydro electric shift on a 14' Larson that has some shifting issues. It does shift into all gears with no problems so I dont think there is a problem with the electical parts. The issues occur once its in gear. Forward is fine at an idle but slips with any throttle applied. You can hear gears slipping. In reverse the engine seems to labor but you cant hear any unusual sounds. Because I am thinking this is a problem with the clutch dog or one of the gears, I have decided to take lower unit out & take it apart to check them. Thought this would be a good time to replace the gaskets, seals, & impeller as well.
I do have a service manual but dont have any experience with these things so any tips, advice, words of wisdom, & general comments will be greatly appreciated.
Here's a picture of the Larson & its navigator who is very upset about the fact that the boat is still in dry dock.

And our victum.

 

[Joe Reeves]

Re: '69 55 hp Johnson hydro electic

Gears, nor the shifter dog, will "slip". If the lobes on either are worn (rounder off), the unit will jump out of gear, then right back into gear, then repeat every so often. This results in an effect that makes one think that they are constantly hitting an underwater object..... quite a clunking effect!

If you are encountering a slipping effect, that is the engine simply speeds up and the boat slows down (no noise, no clunking), that is usually caused by cavitation or a slipping hub within the propeller.

 

[lindy46]

Re: '69 55 hp Johnson hydro electic

No clutch dog in electric shift. Probably a spun prop hub.

 

[Joe Reeves]

Re: '69 55 hp Johnson hydro electic

Lindy.... That engine does not have an electric shift, it is a Hydro Electric Shift, explained as follows.

(Hydro Electric Shift System Explained)
(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)

Note: The engine must be running OR have the driveshaft turning by some other means in order for the engine to shift.

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.

 

[lindy46]

Re: '69 55 hp Johnson hydro electic

OOPS! Sorry - I was thinking Electramatic shift.

 

[Mikko]

Re: '69 55 hp Johnson hydro electic

If the lobes on either are worn (rounder off), the unit will jump out of gear, then right back into gear, then repeat every so often. This results in an effect that makes one think that they are constantly hitting an underwater object..... quite a clunking effect!

Dear Joe,

I am going to test my Evinrude 55 1968 again. It's been sitting for at least five years now. Last time I run it, it worked well, but I remember something like what you described above. I had never experienced it before and it just happened once (couple of times). I thought it was a missfire but as you expalined, it was like hitting an underwater object. Could you explain it in more detail?

Thanks,

Mikko