72 johnson lower unit

adam22

Cadet
Joined
May 3, 2003
Messages
22
I have a 1972 Johnson 50hp two stroke outboard. I recently just removed the lower unit. I removed the water pump and then the bearing underneath the water pump plate. I can't get the driveshaft out though. Is there a set screw or pin or something? Is there any way to check the shift solenoids(hydro-electric shift)? It would not shift into reverse or neutral. I found that the wires to the solenoids were broken, but I want to check the solenoids while I have it apart. Where is this diode that I keep hearing about? Thanks for all your help.
 

alcan

Commander
Joined
Dec 14, 2001
Messages
2,505
Re: 72 johnson lower unit

Hi Adam<br />There is a nut on the other end of the drive shaft called the pinion nut, this nut holds the pinion gear on the drive shaft. In order to remove the drive shaft you will need to remove the prop shaft first. The shift solenoids are located under a cover ahead of the drive shaft. You don't need to remove the drive shaft to remove the solenoids. The diode is wired in the shift circut somewhere. I have found them in several locations. If I were you I would invest a quick $35. for a manual. This will help you prevent making a $350. plus mistake.
 

adam22

Cadet
Joined
May 3, 2003
Messages
22
Re: 72 johnson lower unit

Thanks alcan,<br /> <br />I want to replace all the seals in the lower unit. It had water in the oil. I removed the solenoids, but not sure how to check. I repaired the wires. This thing had 90w in the lower when I got it. I was told that it should only have OMC premium blend. What possible damage to check for? And how to remove prop shaft? I removed the prop. I see four bolts inside the housing behind the prop. Do these allow me to remove the propshaft. Where to get manual and what is best kind? Clymer? I'm new to this outboard thing. I have learned alot by searching the forums. Thanks for help.
 

alcan

Commander
Joined
Dec 14, 2001
Messages
2,505
Re: 72 johnson lower unit

Hi Adam<br /> I believe OMC calls all the gear oil they sell "premium blend" be sure you get the type for elect,gear case. Yes those bolts will be part of removing the gear case head, you will also need a puller. Manuals can be had a lot of places, right here at the top of the page for starts. Book stores,Marine stores,Outboard dealers usually all sell manuals. All the manuals that I've seen are exellent. The OEM publications are nice but defenatly not necessary. If I were you I would choose the book I could get the fastest. Also try the public library.
 

papasage

Senior Chief Petty Officer
Joined
Jan 12, 2003
Messages
785
Re: 72 johnson lower unit

adam i have a shop manual on that motor send me a e mail and i will try to copy what you need if you cant fin what you need .i have had one of those apart it takes a special longnose lockring pliers to git the gears out . e mail me and i will try to copy the info you need and send it to you . papasage10@yahoo.com
 

papasage

Senior Chief Petty Officer
Joined
Jan 12, 2003
Messages
785
Re: 72 johnson lower unit

adam i have a shop manual on that motor send me a e mail and i will try to copy what you need if you cant fin what you need .i have had one of those apart it takes a special longnose lockring pliers to git the gears out . e mail me and i will try to copy the info you need and send it to you . papasage10@yahoo.com
 

Walleye Mike

Recruit
Joined
Mar 27, 2009
Messages
2
Re: 72 johnson lower unit

Hi guys, I have one of the wonderfull hydro-electric shift Johnsons. To be more specific It is a 1971 60HP. I am also having problems with shifting into reverse and neutral. It all worked last year but now this year, NOTHING just forward. I have drained and filled with class "c", and am about to try and energize the solenoids and see if that shifts the motor. IS THERE ONE OR MORE PEOPLE OUT THERE THAT HAVE SUCCESSFULLY TRACKED DOWN AND REPAIRED THIS NOTORIOUS PROBLEM? ALSO ARE THE SOLENOID ONLY ACCESSIBLE BY REMOVING THE LOWER UNIT? Any help would be much appreciated! Thank you, Mike
 

tx1961whaler

Vice Admiral
Joined
May 31, 2008
Messages
5,197
Re: 72 johnson lower unit

Welcome to iboats! It's usually better to start a new thread than resurrect an old one, but yes, they can be fixed. Since yours worked fine last year, I'd suspect that there is an electrical problem with the selector switch or wiring between the switch and motor. The hydroelectric shift requires voltage to shift out of forward, so you should probably start by seeing if there is voltage present on the neutral and reverse lines when the shift is operated. If there is no voltage, then the motor is stuck in forward gear.
I wouldn't go tearing into the gearcase on these units without an OEM manual. There are some special tools required to work on them, and they are quite mechanically complicated.
 
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