1971 johnson 125 electric shift questions

[brickster]

Motor running, 12 volts to knife connectors green wire N, green-blue-R, no voltage-F, will not shift, took lower unit off, opened solenoid housing cover, took solenoids out to check for bad wires and noticed lower unit oil approx 2-1/2 inches from top of solenoid cover, lower solenoid would have been submerged in oil, Is this normal? Had recently replaced lower unit premium blend oil. Need to rule out solenoid problem before focusing on the dreaded oil pump. Thanks for any input,have to keep going with this project, motor is just too nice to part out.

 

[racerone]

Re: 1971 johnson 125 electric shift questions

It should still shift with oil at that level.-------Check ohms on the solenoids.----Report results.----These units are actually very well engineered and reliable.------How long have you owned it and did this problem show up suddenly ?

 

[Joe Reeves]

Re: 1971 johnson 125 electric shift questions

With engine NOT running, is the lower unit in forward gear (normal) OR in neutral (abnormal). If in neutral, the shift plunger is jammed within the oil pump.

 

[brickster]

Re: 1971 johnson 125 electric shift questions

Purchased this motor for $200 last year with no controls and no knowledge of running cond.,but motor appeared in excellent condition for a 71. Compression was 125 all cyl. replaced water pump and lower unit seals, finally found a working shifter, cleaned carbs and it fired right up. Removed original gearcase oil and there wasn't much fluid in there which is why I changed seals and never noticed weather the solinoid chamber is supposed to be full of oil. Can ohms be tested with solinoids out of lower unit?

 

[brickster]

Re: 1971 johnson 125 electric shift questions

With motor not running and turning the flywheel with plugs out and holding the prop it appears to be in neutral. when I removed the solonoids the plunger did not appear to be jammed.

 

[Joe Reeves]

Re: 1971 johnson 125 electric shift questions

Ohms can be checked anywhere, on the workbench, etc.

Engine NOT running.... the prop should turn BUT click in one direction.... and engage forward gear in the other direction so that turning the propeller would cause the driveshaft to turn.

THe plunger I speak of is horizontal within the propshaft and engages the center portion of the oil pump. One CANNOT see the plunger unless the lower unit is dismantled.

 

[racerone]

Re: 1971 johnson 125 electric shift questions

It has to be in forward when the motor is not running !!---------The solenoids operate control valves and do not do the actual shifting !-----You can not see the shift piston / plunger that does the actual shifting when you remove the solenoids.----Test the solenoids , but it sure sounds like a problem with oil pump and shift piston.-------I have repaired many of these units and have seen the oil pump screen deteriorated and pieces jammed in the shift piston bore.

 

[Joe Reeves]

Re: 1971 johnson 125 electric shift questions

(Hydro Electric Shift System Explained)
(J. Reeves)

NOTE 1 -The ohm reading of the individual shift solenoids should be between 5 to 6 ohms. The ohm meter should be set to low ohms. The shift wires leading to the solenoids must be disconnected when being tested.

NOTE 2 - The solenoid plunger measurement must be made with the solenoid placed within the lower unit. The measurement must be approximately 1/64" beneath the top surface of the solenoid... NOT above the solenoid surface nor any lower than 1/64" of the solenoid surface. This factory measurement is critical and will not ever change UNLESS someone has tinkered with it.

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.

 

[brickster]

Re: 1971 johnson 125 electric shift questions

Manual says about 5 ohms between green and blue wire. Does the fluid in solonoid housing sound normal? Would you replace oil pump if it needs to be dimantled?

 

[brickster]

Re: 1971 johnson 125 electric shift questions

Looks like i'll be taking the lower unit apart, sounds like a big job, would you suggest replacing oil pump? How high should the fluid level be in the solonoid chamber after completion?

 

[racerone]

Re: 1971 johnson 125 electric shift questions

First of all both parties advising you here can take your lower unit apart without glancing at a manual.----Both parties could assemble this lower unit if it was brought in as a basket case without glancing at a manual.----You test the solenoids individually.---Blue wire to ground is one test.--Green wire to ground is another test.---Oil will be found in the solenoid cavity and with the level reported it should shift !---You do not replace parts without inspection.

 

[F_R]

Re: 1971 johnson 125 electric shift questions

That isn't what the manual says, or you are reading it wrong. Correct reading is 5 to 6 ohms between green wire and ground, and likewise between blue wire and ground. You do NOT test between the two wires.

I have never had to replace an oil pump yet. But you absolutely do need to know how critical the allowed clearances are. The piston must slide freely in the pump bore, but not be too loose. A couple of thousandths of an inch too much clearance and it won't work. That is why it is so sensitive to fine grit contamination. If that is the case, it needs to be replaced.

EDIT: racerone and I were typing the same thing at the same time. We are agreeing with each other.

 

[brickster]

Re: 1971 johnson 125 electric shift questions

Not getting any reading on my meter, going out to get another and rechecking. I thank racerone and joe reeves for sharing your knowledge and will rule out all possibilities before opening this gearcase.

 

[racerone]

Re: 1971 johnson 125 electric shift questions

Is the unit in forward now ??----

 

[brickster]

Re: 1971 johnson 125 electric shift questions

the unit is in neutral.

 

[racerone]

Re: 1971 johnson 125 electric shift questions

Sound like the shift piston is stuck in the pump bore.------It will alaway be in forward if it is in good shape and not running !!

 

[brickster]

Re: 1971 johnson 125 electric shift questions

Do you have any valuable tips for inspection besides a good manual?

 

[racerone]

Re: 1971 johnson 125 electric shift questions

A factory manual is a must.-----These are precision parts and easy to make $$$ mistakes.

 

[Alexaloisio]

Guys I can't figure out how to start my own thread but I'm having the same problem as this guy. I bought the boat hadn't ran in 4 years. I tune up in a can'd it flushed the very little bit of brown gear case oil with new oil and installed a new throttle cable. Everything went together fine but it won't shift now. I can't get the prop to click either way when I less with the electronic shifter arm in the remote box. I haven't tested the blue or blue green wires yet. Can't find my multimeter. Tell me what I'm missing here. I know this is this internet and I'm giving you guys what I can off the top of my head. Any help is much appreciated. It's the same motor I believe a 1971 125 with electric shift. Prop was clicking and spinning before I put the throttle cable in. Thank you