# The little J-70



## Pappy (Dec 10, 2017)

Here are photos of the little 1.4hp 1934 Johnson J-70 that used to be in my Dad's Johnson outboard dealership in Islamorada, Florida Keys. 
In an earlier thread (A sad but major score) I wrote about how this engine, after around 55 years or so, found it's way back "home"


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## timsmcm (Dec 10, 2017)

She's a real sweetheart, congrats.


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## CedarRiverScooter (Dec 10, 2017)

Very cool!

It has a big prop for 1.4 hp.


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## Pappy (Dec 10, 2017)

Ha! - Found a couple of videos of a running J-70. The one in this video is in better visual condition than mine and is owned by a friend of mine, Doug Penn. 

https://www.youtube.com/watch?v=0AMXXn5nxL0


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## Weldorthemagnificent (Dec 10, 2017)

Pretty neat. Imagine those guys in the 30’s thought they were the cats pajamas on the lake with one of those. 


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## Shaugh (Dec 11, 2017)

Yes it's hard to imagine what it must have been like in those days....Fishing on a big lake and wishing you could to get a couple miles with nothing but oars... an affordable little motor must have been a total revelation.


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## richg99 (Dec 11, 2017)

Fun video and a fun little motor. 

I have to ask...did he just fill it with gas and oil and start it up?

The reason is...I have a mid 50's 2.4 Mercury that I bought at a garage sale (who know why???). I put gas in it a year or so ago, and with a few pulls, she fired right up. I shut her down immediately as I was afraid that I would burn her up. I assumed that the impeller might be shot, even though she was peeing fine. 

Should one rebuild the water pump or at least change the impeller on old engines, that haven't been run in many years, prior to attempting to run them???

thanks


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## Pappy (Dec 11, 2017)

Rich, a 50's engine most likely has a rubber water pump impeller and should be operated as such. Certainly the impeller should be changed as the material will dry rot.
Some, like the Bendix, Eska, Sears, and small Elgins, are air cooled. 

With the vast majority of these older engines, the water pumps were often made entirely of aluminum, or they were a piston driven pump operated off the gearcase, or even a pressure/vacuum system driven off the pressurized water from the propeller blades. The piston driven pumps were a bit more sensitive but these could be run out of water and survive as long as you don't run them for very long. Common sense and feeling the cylinders temp are key.


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## richg99 (Dec 11, 2017)

I think you are saying... Buy and install an IMPELLER... 

Where would one buy such a thing for an older Mercury? I know I have to look up the specifics of the particular motor that I have. thanks


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## Weldorthemagnificent (Dec 11, 2017)

iBoats. 


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## KMixson (Dec 12, 2017)

Weldorthemagnificent said:


> Pretty neat. Imagine those guys in the 30’s thought they were the cats pajamas on the lake with one of those.



Thought? They were!


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## SeaFaring (Dec 12, 2017)

Neat motor!


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## Pappy (Dec 14, 2017)

Thanks for the kind words! 
I started going through the fuel system today. Pulling parts, inspecting and cleaning. There is some gunk in the tank that will take time to remove. Am using OMC Engine Tuner for that. Re-soldered the fuel line onto the carburetor connector and re-bent it properly to take the stress off the solder joint. Will be going through each system and cleaning and resolving any issues that may pop up. Will be fun to put it back into service!


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## KMixson (Dec 15, 2017)

Gunk in the tank? How did that get there? It's a brand new engine just built in 1934. :LOL2:


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## Pappy (Dec 15, 2017)

By today almost all of the crud in the tank was cleaned by the Engine Tuner so I said what the heck....let's do it! To get the rest I threw in some nuts and washers and took a heat gun to the tank and heated the Tuner solution. 15 minutes later it was spotless inside. 
I pulled the carburetor and pulled it apart. Put that in a sonic cleaner as it wasn't very dirty inside. Took a look at the rings through the open intake port and they are super clean and free, no varnish. 
Checked the little water pump and drained water out of the gearcase, put grease in the gearcase and re-installed both pipe plugs. Re-assembled the carburetor after making a gasket for it. Made a gasket for the tank cap out of a carb base gasket for a late model something or other. Inner diameter was perfect!. Put everything back together and threw it in the test tank. 
Took a few tries to find a needle setting it liked as it is very sensitive to adjustment. Ran it for about 20 minutes, ran cool as a cucumber, quiet and smooth for a single cylinder that was built 83 years ago. Once a good needle setting was obtained, the engine could be stopped and restarted easily with no "fiddling" with adjustments.
Guess I may need to do a little video.


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## Stumpalump (Dec 15, 2017)

Heck yeah! Let's see it run.


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## richg99 (Dec 15, 2017)

Well done. I love something from nothing, ......or nearly nothing. 

Not too sure what I'd do with such a small motor. Not sure what I'd do with the 2.4 Merc that I have if I ever get it going, either.

Keep us posted.


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