Johnson Hydro-electric shift question

[Billy Bob]

Hello<br /><br />I've got a question about testing the unit. 1968 model. Another person posted that putting 12v(+) to the green wire while cranking, you should have neutral. And that putting 12v(+) to the green and blue wire while cranking, you should have reverse. Is this correct? Does that further mean than the solenoids in the unit are grounded? In reading about this, I thought there were two solenoids, one each for forward and reverse. What gives?<br /><br />thanks<br />Billy Bob

 

[Joe Reeves]

Re: Johnson Hydro-electric shift question

BillyBob..... In the "Hydro Electric Shift" models, one solenoid is energized for neutral. Both solenoids are energized for reverse.<br /><br />The older model "Straight Electric Shift" models, there were two electromatic coils in the lower unit instead of solenoids. Applying 12 volts to either coil engaged one gear or the other.

 

[P.V.]

Re: Johnson Hydro-electric shift question

Perhaps I can help. If you turn on the ignition key, go back to the wiring and find the two wires that go down "under"/"below" the block. There is a rubber cover that protects the "knife" connector for each wire junction. Just expose the bare connection but don't disconnect the leads. Don't let them touch ANYTHING. With a voltmeter or 12 volt test light, you should have no voltage at either lead. (the lower unit is spring loaded into forward). That's with the control box in forward, If you put the control box into neutral, you should have roughly 12 volts on the green wire only. Once the engine cranks/starts, the activated solenoid will divert oil pressure generated in the oil pump in the gearcase. This will move the spring loaded plunger aft and into neutral. When you move the control box into reverse, both wires are "hot" and the other solenoid also diverts oil pressure and moves the plunger further aft and the clutch into reverse. You must only use OMC Premium Blend oil in this gearcase. Just let it drain and refill with fresh. <br />Now, there is a resistance reading for each solenoid if you want to check. Remove each knife connect and you should have 4.5 to 6 ohms for each solenoid. If you don't have the voltages at the green and blue wires, you have a wiring problem back up to the control box. If you do have the voltages, then you have internal problems.... You can also take a seperate 12 jumper(don't let it touch anything) and activate each wire (green for neutral and green AND blue for reverse as you crank or run the motor. Oh, yea!! Don't let it touch ground!!! BTW, the volt checks with the "key on" checks will not physically put the prop into neutral or reverse no, oil pressure.!!!! You are just checking for proper voltages. Hope this helps !!!

 

[Billy Bob]

Re: Johnson Hydro-electric shift question

P. V. and Cap'n Joe<br /><br />Thanks for your replies. Yes, Cap'n Joe it was your post that I was referring to. The thing is that this is my brothers so don't know much about it. It may not be Hydro Electric. It is shifted by electricity from a box on the side of the boat. It is almost definitely an older set up as it is a 1968. Like I had mentioned, the manual suggested one wire control forward and one reverse. What I really want to know is; could the book be wrong?? <br /><br />thank you<br />Billy Bob

 

[Joe Reeves]

Re: Johnson Hydro-electric shift question

BillyBob.... In 1968, the shift setup could be either system. This is due to the fact that the "Hydro Electric" shift was introduced in 1968 with the 3 cylinder 55hp model, but the various other models still incorporated the straight electric shift setup. This is why it is so important to list the "Model Number" of whatever engine one is speaking of.<br /><br />If one doesn't list the model number or list the exact mfg, year, hp of the engine, it would be something like say (pertaining to a truck) "Why won't my truck hit 2nd gear"? Nobody would know if it was a V/6, V/8, straight 6, automatic, stick, Ford, Chevy, etc etc.<br /><br />Let us know exactly what engine you're speaking of and we'll get back to you.

 

[seahorse5]

Re: Johnson Hydro-electric shift question

Billy Bob,<br /><br />If the exhaust goes thru the center of the prop, you have the hydraulic shifted electrically activated gearcase. <br /><br />If you have a prop with a drive pin (shear pin) in it, you have the electric shift gearcase, with springs and electro-magnets.<br /><br />Follow Joe's and P.V.'s advice and tips

 

[Billy Bob]

Re: Johnson Hydro-electric shift question

Joe and Seahorse<br /><br />Thanks for the replies. My motor is the RKL 30<br />40 horse motor. Given what you said about the exhaust, it would be the latter. The prop has the shear pin.<br /><br />Now the question is, how should this thing work electrically speaking? <br /><br />thank you<br />Billy Bob

 

[P.V.]

Re: Johnson Hydro-electric shift question

WELL !!!! Now that we know the finer details......<br /> In an electric shift system, when the control box is put into forward, 12 volts energizes the forward shift hub. So check the green wire to see that it's getting the 12 volts. When the control box is in neutral, no power goes to either the green or blue wire, In reverse, 12 volts goes only to the blue wire down to the exhust/lower unit. When you check for this voltage, remember that the integrity of the gear oil (premium blend only) must not be contaminated by water, dirt, etc... <br />The system works like this. All the gears rotate all the time.. Actually, the gears each turn a large "hub", that's slightly knerled, the shift spring is connected to a coil and when activated by the 12 volts, is magnatised and collapses onto the outer portion of the hub. It "grabs" the hub and locks the gear into/onto the prop shaft. Remove the 12 volts, the spring releases it's tension and unbinds the hub. Often the end of the spring breaks, so no action is noted. Often spring breakage is caused by shifting at too high an idle speed. Or manfunctioning shift switch in the cintrol box....Hope this helps !!!

 

[Billy Bob]

Re: Johnson Hydro-electric shift question

PV<br /><br />Why yes it does help. Will now go through a test. AFTER, I install new gear oil. This is a recent acquisition so have lots of things to look at. Basically SEEMS solid. After a little carb clean up, motor fired like it should. The shift and water pump are still holding us up. <br /><br />Thanks to you and a few others, the shift problem should be going bye bye. That is, if the test indicates nothing wrong with lower unit. Hopefully the water pump prob will resolve too.<br /><br />thank you<br />Billy Bob