New Motor Questions, 1950 Johnson SD-20

This topic has 45 replies, 17 voices, and was last updated 8 years, 6 months ago by sedover.

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June 20, 2015 at 1:38 am #1798
david-bartlett
Participant
I just acquired a 1950 Johnson 16HP. Not even here yet, as my son is bringing it to me tomorrow. I have never seen one in person, just on the internet, and was wondering what insight the group might have for me regarding what to look for.

It is interesting in that it has a spark advance lever independent of the throttle, which I guess is really not much different from how things started out, just had not seen one before.

I think these do not use the universal mag common on later motors, and the points are the plunger type.

Will be fun learning about rotary valves and all that goes with it.

I will get some pictures up when I get a look at it.
June 20, 2015 at 4:16 am #18477
legendre
Participant
Check your PM
June 20, 2015 at 10:56 am #18489
gjonz
Participant
Great motors! Lots of torque. Go through the ignition. No water pump to,deal,with as it is a pressure vacuum system. Lower unit seals if needed are available at Sea Way Marine.

I have several. Always dependable.

Greg
June 20, 2015 at 1:34 pm #18492
beerman57
Participant
Seaway doesn’t have parts lists for OMC like they do for Mercs. Call them at 800-332-0803.
June 20, 2015 at 2:24 pm #18497
jeff-register
Participant
US Member - 2 Years
When working on the points there is a plunger shaft that actuates the points. Be sure to replace them the same way they came out. One end is flat & the other is rounded
June 25, 2015 at 12:53 am #18859
david-bartlett
Participant
Thanks guys for the replies. I have been away from internet access for a few days and just got back. Here are a few pics.

As you can see, a mouse family had moved in and taken up residence some time ago. Compression is good, but no spark yet. I have not pulled the flywheel to clean the points yet, but will soon. I need to clean the carb as well.

More questions to come!
June 25, 2015 at 2:08 am #18868
ray-schaber
Participant
Clean the engine with a strong bleach solution. Mouse droppings can have many germs.
The mouse smell may last for a year or more.
Ray
June 25, 2015 at 2:23 am #18869
davidk
Participant
US Member - 2 Years
Why is there a round panel in the side cowling on David’s first photo? Just saw this on a friends QD10 and we couldn’t figure out why that panel is there?
June 25, 2015 at 7:05 am #18884
legendre
Participant
quote Jeff Register:

When working on the points there is a plunger shaft that actuates the points. Be sure to replace them the same way they came out. One end is flat & the other is rounded

And apparently, that means the flat end runs on the points cam (flywheel side) and the rounded end runs on the moving points contact. Was news to me.

quote david bartlett:

More questions to come!

Questions like, "Hey guys, what are the symptoms of hantavirus and septicemic plague"?

😀
June 25, 2015 at 10:37 am #18889
1946zephyr
Participant
very interesting motors. Never had one myself. but that cooling system was always interesting to me. I don’t have anything to input here, but you have a cool looking motor. Nice shape too.
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