Antique Johnson Outboards

For pre 1975 outboards and race motors only.

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Rapier
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Re: Antique Johnson Outboards

Post by Rapier »

Finished the front of the motor yesterday, cleaned the simple carb and the handle and tiller - also very clean in both bores, pistons are clean and unscored and rings clean - it doesn't look like the motor has done a lot of work. Issues were a stuck decompression valve - that gave up after a bit of heat applied and an old repair to the exhaust valve that I tightened up with a brass punch and filled with chemical metal. Pile of bits that were cleaned up and lightly polished today - the exhaust manifolds are notoriously dirty with baked on carbon and fiddlely to clean externally. Not quite sure what to do with the 2 asbestos plates that prevent heat transfer to the fuel tank above - if anyone has a bight idea for a replacement or a means of sealing them please let me know...Unfortunately the magneto plate is also devoid of any electrical bits, bar a half set of points...used items are on the way from the US, as this shares common parts with other P model Johnsons.
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P1210537 (Medium).JPG
P1210540 (Medium).JPG
P1210541 (Medium).JPG
P1210543 (Medium).JPG
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Rapier
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Re: Antique Johnson Outboards

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Been trying to scrape all the burnt-in deposits from the exhaust manfolds, so far a small gas torch does the trick. Yesterday the magneto plate arrived - like christmas in July.
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Re: Antique Johnson Outboards

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After pic. Hoping nigh 90 year old electrics will do their stuff...
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Re: Antique Johnson Outboards

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Ready to go. I have been mixing fuel and this motor, a Big Twin, uses 1 US Pint per US Gallon, which equates to an 8:1 mix! In layman's terms this is 125ml oil per litre of fuel. Ouch. Pics to follow.

I got rid of the asbestos and replaced with an airspace and a 3mm ali plate - it should work to dissipate the heat.

Started 3rd pull, but the post event video doesn't show this :hmmm: . I think the float level's too high and the starting instructions for such a behemoth may not be the same as the 2-3hp Light Twins. Startup is at 2mins 17.... :heat:

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Re: Antique Johnson Outboards

Post by Rapier »

The finished article. Just need to fine tune!
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1929 P45 12hp.JPG
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Re: Antique Johnson Outboards

Post by Rapier »

Exhaust relief on this motor was stiff to operate, so I replaced the solid cable with a cheap lawnmower clutch cable - now works a treat.
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Re: Antique Johnson Outboards

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This AAL-37 (1937 longshaft) 4.5hp came home with me recently - it is/was my very first antique outboard, bought from boat trader. At the time it was hard to find spares for, but it sparked then and had hefty compression - it had been used to fish on the canal a few months before I bought it by an elderly gent from Nuneaton who'd owned it most of his life. This model is an alternate firing twin and very sophisticated in comparision with the 1920s Johnsons. It has twin coils and points in common with modern OMC 4.5s and a special carb / throttle linkage to the mag plate and high and low speed needles. They're also a lot quieter than the opposed twins...

It longer sparked, so I popped the flywheel and cleaned up and set the points, cleaned the carb and am now cleaning the tank, which at least was drained all those years ago. Planning on leaving it aluminium - they were painted silver.
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Johnson '37 AA37.JPG
40841189_2_x.jpg
112-1243_IMG (Medium).JPG
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P1210731 (Medium).JPG
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Re: Antique Johnson Outboards

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Not the most attractive of antique outboards, but it is 80 years old...It has a slight grease leak from the prop seal, which I'll just keep an eye on. All ready to fire up though & 16:1 mix, so less smelly than the P-45.
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1937 Johnson AAL-37 4.5hp
1937 Johnson AAL-37 4.5hp
1937 Johnson AAL-37 4.5hp
1937 Johnson AAL-37 4.5hp
1937 Johnson AAL-37 4.5hp
1937 Johnson AAL-37 4.5hp
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Re: Antique Johnson Outboards

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I've had this little Seahorse 3hp for many years; it's not an antique, but these and the Evinrude Lightwin 3 & 4hp are such amazing motors - light, quiet, powerful, 50:1 mix and easy to maintain. Which is why I've a soft spot for them - until I owned this one. Spent the normal on a service kit and got it running a long time ago, but it never pumped water properly and overheated too quickly- these have no telltale, merely blowing a spray of water and exhaust out of a few small holes in the leg. So I left it..Realising I might be able to convert a certain barrow boat owner to the joys of reliable ownership, I thought I'd get it running properly for Cardiff.

I must have dropped the leg 8 times, dismantled the midsection twice (to make a new gasket the 2nd time around), run it with a drill on the drive shaft, checked the water tube for kinks and blockages, sealing the wear plate and pump and clearing out an all important primer hole in the pump, before finally biting the bullet and using one of my stock head gaskets to do what I should have done a long time ago. Maxrules has a great resource for these 3hps which I've used on at least 3 other of these motors, so is an easy fix.

http://www.maxrules.com/fixtuneitup.html

Removing the head (plenty of heat and only one broken bolt) it was obvious what he the problem has been all along. Some would say the evidence of loss of paint & primer is an indication, but that's just an OMC thing..It works now..I think...At least it ran happily for 30mins in my test tank. We shall see...
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P1210773 (Large).JPG
P1210777 (Large).JPG
P1210781 (Large).JPG
1967 Johnson Seahorse 3hp
1967 Johnson Seahorse 3hp
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Re: Antique Johnson Outboards

Post by Rapier »

Interesting racing plug to be used on the 1929 Johnson P-45.
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