hydro electric shift gear case solenoids...

Joined
Aug 20, 2009
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2
boat motor rookie here,
I have a 1968 johnson 55 hp that is stuck in drive, i have determined that there is something wrong with the shifter solenoids, i would just like to know how to get into the gear case to remove and replace the solenoid, that is, if they are located there. Also, I have reason to believe that the stater is shot. is this an easy fix? (stater). Would this be an expensive job?
 

tashasdaddy

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51,019
Re: hydro electric shift gear case solenoids...

well finding good solenoids is major hurdle. they are no longer manufactured, and good used ones extremely rare. as far as the stater, not that hard, but you really need to be sure that is what the problem is. there are only a few new ones left, and expensive, also the Amplifier(power pack) is expensive.

the motor has to be running for the lower unit to 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.
 
Joined
Aug 20, 2009
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Re: hydro electric shift gear case solenoids...

tashasdaddy,

well thanks alot, this information will prove to be very useful, i will post any further troubles... muchly appreciated.
 

Daviet

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Sep 24, 2008
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8,958
Re: hydro electric shift gear case solenoids...

You may also want to pick up a factory manual for your motor. Lots of repair information and will help to trouble shoot problems. Just sayin.
 

R.Johnson

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Sep 24, 2003
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4,446
Re: hydro electric shift gear case solenoids...

Was there water in the gearcase?
 

mikep1220

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Aug 30, 2009
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Re: hydro electric shift gear case solenoids...

i have tried this to see if my switch was broken and the motor still runs in foward gear? im starting to this it may be seized if thats possible. does anyone know what might be the cause if it being stuck in foward
 

Daviet

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Joined
Sep 24, 2008
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8,958
Re: hydro electric shift gear case solenoids...

If you checked it out according to tashasdaddy's instructios and still can't make it shift you are going to pull lower unit. You either have an electrical or pump problem in lower unit. No cheap fixes there.
 

mikep1220

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Joined
Aug 30, 2009
Messages
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Re: hydro electric shift gear case solenoids...

yea i have a feeling its something in the lower unit. when i checked it on my luch break there was oil leaking from behind the prop. i think im goin to have a mechanic take a look at it
 
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