1972 Johnson 65 selectric lower swap

[TommyRocker]

I've got the aforementioned Johnson that runs like new but has a weak reverse. I haven't opened it up but it seems to function correctly electrically but sounds like skipping clutch dogs. It's a long shaft. My question is, if I find a matching short shaft lower can I just swap them out or are there obstacles?
Thanks for your help

 

[racerone]

???----You would have to swap the driveshaft.----OR it would be simple to swap the clutch dog and reverse gear.----But what if there is low oil pressure or shift piston is not moving correctly ???----Your location ?

 

[TommyRocker]

I'm on the Wisconsin/Illinois border on the chain o lakes. Yeah, I haven't dug into the lower unit yet, I'm still restoring the boat I got it on but it's a long shaft and a 15 inch transom so it would've been nice to kill 2 birds with one stone. Was hoping finding a complete lower from a short shaft would do it but I wasn't sure since I haven't had it apart yet.

 

[jimmbo]

If your 65hp is a Long Shaft, there is no way a Lower Unit with a Short Shaft is going function on it. The 5 inch Difference is in the Midsection/Exhaust Housing. The only difference with the Lower Unit, is the Length of the Driveshaft. With a bit of work, you can swap in the Longer Driveshaft, and it will work, but only as a Long Shaft
It is a lot of Work to replace the Midsection/Exhaust Housing and all the parts within. A Jackplate might be able to raise the Longshaft up 5 inches

 

[racerone]

Need a short midsection ?-----Not hard to find in some sheds.

 

[TommyRocker]

Thanks for the info. I was hoping it was a more elegant design than that. Sounds like a jack plate will be in order if I can remember the slipping gear

 

[jimmbo]

You will have to tear the unit apart to inspect the Pump. Those Hydro Electrics are usually very Reliable, shift very fast, resulting in Minimal Wear on the Clutch Dog, and Gears. Of course if they suffer from Low Oil Pressure, that changes it

 

[racerone]

I can tear one apart / diagnose / repair / re-assemble without needing to look at a manual.----So I think they are simple.

 

[F_R]

Tommy, I think it is a mistake to assume the problem is in the lower unit. I wouldn't tear into one without using a jumper wire to bypass the external electrical system as a diagnostic test.

 

[TommyRocker]

Tommy, I think it is a mistake to assume the problem is in the lower unit. I wouldn't tear into one without using a jumper wire to bypass the external electrical system as a diagnostic test.

It functions electrically and appears to work perfectly on muffs. In the water when there's a load on the prop it sounds like it's grinding in reverse. I'm not sure where else to look but in the lower unit. The motor wiring is all in nice shape, it's got fresh type c oil. I'm not going to dig in yet, I've got another boat we've been refreshing that I just finally splashed a few days ago so we'll be spending time on that this summer and the boat the Johnson is for us still upside down waiting for me to get around to the painting or gel coating it. It's a 1959 so I'm not even committed to using the Johnson on it. Would've been a convenient stop gap if it was that easy.

 

[jimmbo]

I can tear one apart / diagnose / repair / re-assemble without needing to look at a manual.----So I think they are simple.

You've done many, maybe several hundred. I bet the first time you took one apart you read and reread the Manual

 

[F_R]

I8

It functions electrically and appears to work perfectly on muffs. In the water when there's a load on the prop it sounds like it's grinding in reverse. I'm not sure where else to look but in the lower unit. The motor wiring is all in nice shape, it's got fresh type c oil.

I knew you would say something like that. What gets me is that people will balk at a simple 5 minute job to test and verify.

 

[racerone]

Just the way it is.-----Years ago fellow showed up with a 66 model V-4 Evinrude electromatic.----Said reverse did not work and big dealer had said ---" not worth fixing "------I took cover off control box to find wire had fallen off the push button shift switch.----Seems that as soon as the word ----electric -----is involved it becomes complicated.

 

[jimmbo]

Complicated: Electronic yes. Electric no

 

[TommyRocker]

I8


I knew you would say something like that. What gets me is that people will balk at a simple 5 minute job to test and verify.

I'm not balking at a 5 minute check, I'll do it before I drop the lower. But I have to drop the lower anyways to do the impeller. And I'm not sure how it could shift into reverse if it wasn't getting power to both solenoids. I'm under the impression that no power is forward, power to neutral solenoid is neutral, and power to both is reverse. If I was only getting neutral and forward that would be my first check but I'm getting all three and classic worn clutch dog symptoms. As I've said, I won't be digging into the motor for a while yet anyways but I'll be sure to check voltage at the wires.

 

[F_R]

OK, so I got you to consider doing an electric test first. That was my only aim.

You are basically correct in your understanding of how it works. But why it doesn't work is important too.

First, you referred to it as "Selectric". That is Evinrude's version. Johnson's were "Hydro-Electric". Totally different remote controls, and either will work. It pains me to say it, but Johnson had the more reliable control.

When you put the control in neutral, 12V is sent to the neutral solenoid. and 12V is sent to both neutral and reverse for reverse. But suppose one of those 3 switch contacts is corroded or burnt and one of the solenoids is only seeing 3V in reverse? The solenoid won't hold the oil valve tightly closed and it may not be pushing the dog tightly against the reverse gear. See where I'm going with this?

Inside the gearcase, the #1 cause of failure is dirty oil. Not big chunks of rocks, but microscopic metal dust---the stuff that turns the oil black. The stuff that jams the piston in the oil pump. Once that happens, it is too late. Changing the oil won't help.

 

[TommyRocker]

The old oil looked fine when I changed it but who knows if it was garbage before that and the previous owner changed it recently to hide the fact. Thank you for your advice and sharing your knowledge. When I have time to pivot back to this boat I'll verify voltage first.