1969 55 hp shifting problem

bl19811

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I have a 1969 55 hp hydro electric. I am having problem shifting, I put it in nuetral and it goes forwar, forward goes forward, but in reverse, the prop does not spin. Could this be related to bad seals in the lower unit.
 

F_R

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Re: 1969 55 hp shifting problem

Yes, it could in the sense that leaking seals have admitted water and caused damage inside. If that's the case, seals alone won't help. But before you jump to conclusions, do a voltage test at the shift wire connectors by the powerhead. Could be a bad shift switch or wiring problem. There are plenty of threads here that you can search for on the subject.
 

tashasdaddy

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Re: 1969 55 hp shifting problem

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.
 

bl19811

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Re: 1969 55 hp shifting problem

If the seals are bad what else could be wrong?
 

tashasdaddy

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Re: 1969 55 hp shifting problem

oil pump, solenoid, due to water intrusion. rusted gears, bearings.
 

bl19811

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Re: 1969 55 hp shifting problem

I have only tried running with the engine with the muffs on? Could this be why the prop only spins forward in nuetaral and foraward, and doesent spin in reverse? The guy I bought the engine from said he replaced the seals. Is there a way I can test it with out actually putting the boat on the lake?
 

tashasdaddy

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Re: 1969 55 hp shifting problem

the motor automatically defaults to forward, if you are not getting voltage to the shift control wires. it is not going to shift to neutral or reverse. now the prop will turn slowly in neutral do to the exhaust turning it.
 

ftltony

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Re: 1969 55 hp shifting problem

I have a 1969 55 hp hydro electric. I am having problem shifting, I put it in nuetral and it goes forwar, forward goes forward, but in reverse, the prop does not spin. Could this be related to bad seals in the lower unit.


In Neutral, is it "spinning" or is it just "turning"..????

My 225 "turns" in Neutral. In forward, it goes forward as well. It sounds like Tasha's last post hits on what you need to check. Maybe you have a bad wire/connection to the solenoids that shift the motor.
 

tashasdaddy

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Re: 1969 55 hp shifting problem

he could have bad shift switch, bad connections, bad solenoids in lower, damaged wire to solenoids in the mid section.
 

bl19811

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Re: 1969 55 hp shifting problem

It is spinning. and reverse doesn't turn at all. does it sound like a bad switch or could my seals have something to do with it. Even though since they have been replaced it hasent been in the water.
 

F_R

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Re: 1969 55 hp shifting problem

No spin at all in reverse? Time to get off the seals kick and do as everybody has already suggested. ALWAYS start the troubleshooting on that motor by checking the oil in the lower unit. If that is OK, move on to testing the electrical system, beginning with voltage tests at the blue and green wires that dissapear down to the lower unit. Only after the electrical system is proved to be OK should you even consider going into the lower unit. You never do a heart transplant on a guy before giving him an EKG.
 

bl19811

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Re: 1969 55 hp shifting problem

DO i check the voltage going to the solenoid or the shift switch?
 
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