Johnson 2R72M

[Mumbles]

I’m not sure if that is one long shaft or not but if it’s a two piece with a Sprag clutch it may be an electric starter!

[dan-in-tn]

Looks like it might possibly be an OMC trolling motor that has been adapted for some reason. OMC trolling motors have a solid aluminum mount on one end that is thick enough to be the end hooked to the front of the gearcase. Now the problem with that assumption is the other end would have a hole in it sticking forward where the trolling motor propshaft would normally stick out. Slim60, is that plugged up somehow? The armature and brush holder look OMC. Of course it can’t work full of oil and water. Slim60, does the outside body of the motor seem to have a place where a skeg has been ground off the motor body. It was a steel skeg, about an 1/8" thick welded on. The yellow wire should run the length of the motor to the brush holder which is to the front. Again I have no idea what the apparatus was being used for. If there was a way to dis-engage the powerhead, it would make a quite trolling motor steered from the transom, but not sure how the powerhead would be de-coupled. Beats me! Looks like some work went into it.

Dan in TN

[billw]

Seems like a small motor to be propulsion…what about a small generator? Very cool/weird, whatever it is.

Long live American manufacturing!

[fleetwin]

OK, well the gear isn’t fixed to the prop shaft so the electric motor must somehow be able to spin the prop shaft without having to move the gears/powerhead. That small gage wire doesn’t seem large enough to run the electric motor though.
The prop shaft must be able to pull out of that housing somehow to expose that pin.
Very unique unit indeed, hard to say if it is some sort of engineering "one off", or perhaps an outside vendor add on. Would have been an expensive kit though that would have included a new gearcase housing.
The electric motor section seemed dry, or perhaps you cleaned it up, you will need to inspect/replace the gearcase.
I wonder where the gearcase fill/drain screw is, the electric motor blocks the usual location.
A unique engine indeed, put it away and preserve it once repaired.

[slim60]

The strange part for me is, this is my first Johnson. My friend who owns the recycling center told me the kid who brought it in said it was his deceased father’s and it was a prototype.

[fleetwin]

OK, so this is a one of a kind unit. Can’t wait to figure out just what it is and how it works!

[terriblecj]

Indeed, strange. Wonder who his father was and if we could find out if he maybe worked for Johnson R&D or maybe a 3rd party company that used the Johnson as a test-bed. Pretty darn cool either way you slice it! Great find

[chris-p]

Can it just be a generator used to charge battery, or accessories somehow? Instead of a belt, it runs off the prop shaft. Strange indeed, never seen anything like that before!

[billw]

I’m not really clear with the pictures….is there, or is there not, a conventional drive shaft and pinion gear? I’m not so much caring how it drives anything right now…I am just wondering if they are THERE? (If not, what was the point of having a gas motor connected to nothing?)

Let’s suppose I was a Johnson engineer with big dreams and time on my hands. What I might try to make would be a hybrid outboard…When the conventional gas power head ran, it would drive the prop and the electric motor, which might function as a generator to charge a battery. Then, fishing, the electric motor would be able to drive the prop shaft directly with some kind of clutch that would maybe centrifugally disengage from the gear.

Hey, what do I know? Why not? Maybe the engineer went on to Toyota and made the Prius.

PS…I can’t believe this is your first Johnson? What are you going to do for an encore, when you get a second one? A Wankle? Gas turbine?

Long live American manufacturing!

[slim60]

I can’t believe a rooky like me stumped the experts! For my next trick I’ll buy a Johnson that runs on water. lol…So I started cleaning and the yellow wire that was lodged in the magnets fell out. It has a loop connecter on it. Looking at the brushes one is grounded. So the yellow wire should go to the other brush assembly? BillW I removed the pinion and drive gears. They did not spin the prop when I tank tested the gas engine.

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