Early Johnson Waterbug? Model A? Model AB?

[dougbok]

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I picked up this old Johnson today at a local Habitat store this morning. I went online to figure out the year and model because there is no model number apparent on the rope pulley (see photo). I saw it referred to as a Waterbug or a Light Twin and I think that’s what it is. I also think it is a pretty early one, it looks like it doesn’t have the larger intakes of the A-25. The serial number seems to have a "B" in front of it followed by 2467.
I saw a reference to a model "AB" in the model listings. Can anyone tell me what it is and possibly what year it was made?

[dougbok]

Looks like the photos I tried to upload didn’t make it. I’m a new member and don’t know the ropes, perhaps I did something wrong or it is not allowed.
Perhaps someone can tell me the process and if possible I’ll try again to post them.

[PM T2]

saw your photos in the first post you did, they showed up there.

Larger "intakes" I think you have that term confused, do you mean "exhaust manifolds" because these motors don’t really have an "intake" per se, just a cast neck on the front of the crankcase, and those are mostly all the same.

Yours does have the later A-25 foot on it where the lower unit housing brace arm connects to the anti-cavitaion plate, whereas the earlier Johnson lower unit used a plate that was separate (and optional) and the brace was independent of the anti-cavitaion plate.

Check the underside of the crankcase where the cylinders bolt up to it and see if you find a serial number stamped in there. That number is supposed to match the one on the rope sheave.

IF – and I say "if"- the serial number on your motor is genuine, then it would would have been a Model B built in 1923. The "B" was a salt-water motor versoin of the Light Twin model "A", but it did not have a brass lower unit. It would have had corrosion materials used for the driveshaft, propshaft, and possibly the gears (not certain about that tho).

It may be possible that you’ve got a 1923 motor that received a later lower unit as a retrofit to replace a worn-out or damaged original foot.

Hope this helps.

Best,
PM T2

He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...

[dougbok]

Thanks for all the great info!
I know nothing about these models so your detailed information is appreciated The "intake manifold" comment came from a YouTube video on the A and A25 motors which showed two different cylinder castings. He referred to them as "ports" and I assumed they were intakes as they are behind the carburetor…
the video was nicely done.

https://www.youtube.com/watch?v=IaGfpGfju8Q

The number stamped on the crankcase by the cylinders looks like A1844 so the number by the rope pull is probably bogus.
This makes sense because it was crudely stamped.

Thanks again.

[PM T2]

Its a case of good news/bad news for you.

Sort of bad – The serial numbers don’t match, so that more or less tells you that it’s not made of all original parts.

Good – the serial number you are reporting on the block is lower than what you see on the rope sheave.

Sort of bad – it doesn’t appear to be a model B salt water motor.

Good – its IS a very low serial number A, one of the first 1500 built. IN fact, if the 1844 is correct, it would be the 1338th Johnson ever built.

Good news is you have the hard cast tank and correct flywheel/megneto set up for that motor. Bad news is you have a much alter vintage gas cap on there at the moment.

THe lower unit is an A-25 era foot, so it suggests that either

a) a replacement foot was substituted after the original wore out, or
b) the powerhead was swapped onto a later A-25 tower and foot.

I’d guess "A" based on your motor having a grab bar that appears to be rusted where the plating has peeled away. Check the grab bar and the driveshaft tubing with a magnet. If the magnet is attracted to those tubes, it would indicate those are the early parts that were made of steel, as opposed to the later grab bars and driveshaft tubes that were nickel plated brass.

Hope this helps eh

Best,
PM T2

He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...

[dougbok]

More great information. The driveshaft tube and handle are both steel. It’s nice to have an idea what it is but this is one I’d just like to clean up some and get running. The water pump looks like it’s been crudely soldered so I’ll probably need to put a WTB classified ad in for a replacement. The plug wires are shot so there’s another project.
What’s neat is that the remnants of the original grip was stuck in under the crankcase and a grungy old pouch with shear and cotter pins was wired to the motor. Also like the old Allstate spark plugs.
If these things could talk I’d bet there’d be some stories to tell. I’m glad someone decided to try to find it a home rather than throwing it in the metal bin at the transfer station.
Thanks!

[stanley]

Leather grip?

[dougbok]

No, the grip is rubber but very old. Not usable but I’ll save it anyway. I was told the lower unit was later so it may be from the same motor the lower unit was from.

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