Topic: 1951 Johnson rd-11 – Antique Outboard Motor Club,Inc

This topic has 11 replies, 8 voices, and was last updated 9 years, 6 months ago by olcah.

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May 18, 2015 at 3:36 am #1524
joshadurham
Participant
Anyone have experience with this model Johnson? I just found one that I might buy, and know nothing about it. It’s in decent shape and is complete. I have a cd-13 5.5hp and love it.
May 18, 2015 at 4:11 am #16294
opposedtwin
Participant
US Member
I have had a number of the early big twins over the years and love them. they run great when they have good compression numbers. if it’s less than 100 lbs, you’ll have trouble getting it to idle well. they’re a bit noisier than the later models like the 1955 and newer ones. take a compression tester with you and check the compression in both cylinders. easy to work on. you’ll love it.
scott
May 18, 2015 at 5:16 am #16298
legendre
Participant
I have no experience with that model, but any Johnson motor of that era should be a good bet – assuming it wasn’t abused to death. They had some decent engineers on-board.
May 18, 2015 at 1:59 pm #16325
chris-p
Participant
As stated, they are great motors. A bit louder than the ’55 and on as Scott stated due to design. parts can be a bit more troublesome to find than the ’55 and on as well, but with the forum here it is not that difficult.
May 19, 2015 at 1:49 am #16400
david-bartlett
Participant
Josh,

I have an RD-16 which is the same thing, just a couple years newer. Very neat motor. Easy to work on. Ignition components and carb kits readily available.
The way the cowling attaches makes it a bit harder to access things, and makes for some extra vibration noise, but hey, it is 60 plus years old and still going.

Make sure you run at least 24:1 fuel/oil mix, and preferably 16:1.

Here is a pic of mine with my JW-11.
May 19, 2015 at 3:15 am #16408
joshadurham
Participant
Thanks for the responses! The guy is set on $175.00. Seems high to me. Thoughts? He says it runs, and maybe it does, but cosmetically speaking, it’s bad. All scratched up. Can’t even read Johnson on the side.
May 19, 2015 at 3:27 am #16409
david-bartlett
Participant
Josh,

I think you are better off starting with a good running motor over a good looking motor. Best if you can get both, but that’s life.

JMHO
May 19, 2015 at 3:49 am #16411
joshadurham
Participant
Yea I got lucky with my Johnson cd-13. Looks good and runs perfect for a bargain, and came with a tank and fuel line.
May 19, 2015 at 7:20 am #16419
frankr
Participant
US Member
At the dealership where I worked at the time, once the quieter motors with flip-up hoods came out in 1955, after a couple of years we could hardly give away used Pre-1955 25hps. Now they are popular again. Isn’t it funny how things work out?

I don’t think $175 is unreasonable, but condition is everything. So is location.
May 26, 2015 at 12:24 am #16883
joshadurham
Participant
Went and looked at the RD-11 today. Compression was an even 88 on both cylinders. Basically everything that was supposed to move was gummed up from non use. And there was no spark. The motor was covered in crusty salt looking deposits. It did shift correctly. But in the end due to lower compression, and the no spark, I passed. And I now know that I prefer the hinged motor cowl. The cowl on this 51 was a pain to remove. The search continues.
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