1972 65hp Johnson Hydro Electric Shift Lower Unit Issue

[rsamsel]

Hi guys-

Ill try to keep this as concise as possible to try to keep it easy.

Bought a boat with a 1972 65hp hydroelectric shift. Reverse was OUT on the boat. It was out MECHANICALLY and has nothing to do with a hydro electric shift problem. It tries to shift into reverse but grinds b/c the gear is tore up. I used the boat with forward and neutral only for 6 months and it worked perfectly.

Four month ago I came across a new/used lower unit. Changed to the new lower unit and it worked perfectly in all regards (forward, reverse, and neutral) for the last four months...maybe 10 days out.

Two days ago went out and had forward and reverse only. No neutral. Went to check the fluid (it was type C) and it was totally milky and CRAP. I know I should have been checking it better but that doesn't matter now. I changed the fluid to new Type C and I still can't get it to shift into neutral. Have forward and reverse only.

Questions:
1) Would running the bad fluid have cause this (obviously it did) but what happened do we think? I assumed putting new fluid in would allow it to start shifting again but no dice.
2) How hard of a job would it be to tear into both lower units and put the reverse gear from the new/used unit into my original unit that clearly has a stripped reverse gear but shifts great?

ANY more info you need let me know. Crabbing seaon is still open so I'm anxious to get her back on the water.

Ps..I checked the voltage at the green and blue wires and it seems to be what is should be.

 

[boobie]

Better check your shift switch first.

 

[racerone]

You say " voltage seems to be what it should be "-----means very little here.--------What voltage on green in forward ?------What voltage on green when nuetral is selected ?

 

[rsamsel]

Better check your shift switch first.

I'm not sure I know what this is...how to check.

 

[rsamsel]

You say " voltage seems to be what it should be "-----means very little here.--------What voltage on green in forward ?------What voltage on green when nuetral is selected ?

Well I should have tried to check it like that. Maybe I lied a little accidentally. I manually gave the green wire going to the lower 12v and it was still stuck in forward.

 

[racerone]

edit

 

[rsamsel]

I did try to manually power the green wire to get neutral but never got it to do anything other than spin forward. I wasn't able to get a reading that made any sense on my volt meter on the motor side of the blue and green wires. I think i was struggling to get a good ground.

 

[F_R]

Actually, reverse gear requires proper voltage on BOTH wires at the same time. Also, both the neutral and reverse hydraulic valves and piston have to be working to go to reverse (has to go through neutral to get to reverse). That would seem to indicate that the wires and solenoids as well as the hydraulics in the lower unit are all ok. So what else remains? I have to think the shift switch in the control is not providing proper voltage to the green wire in neutral position, but is supplying voltage to both wires in reverse position. Just an educated conclusion.

 

[rsamsel]

Actually, reverse gear requires proper voltage on BOTH wires at the same time. Also, both the neutral and reverse hydraulic valves and piston have to be working to go to reverse (has to go through neutral to get to reverse). That would seem to indicate that the wires and solenoids as well as the hydraulics in the lower unit are all ok. So what else remains? I have to think the shift switch in the control is not providing proper voltage to the green wire in neutral position, but is supplying voltage to both wires in reverse position. Just an educated conclusion.

Ok...so trouble shooting would be a volt meter on the green wire with the engine running correct? Should be 0v in forward gear and should go to 12v when placed into neutral correct? Also I assume the only way to test this is to actually start the motor instead of just cranking?....because the motor wont crank in forward...

 

[racerone]

Facts are,if the lower unit is not turning it will not shift.-----The lower unit is in forward when not turning.----With control in nuetral it will shift from forward to nuetral after about one turn of the crankshaft.----Only if the lower unit is in good condition.