1954 Johnson Seahorse 10 hp data

zul8tr

Cadet
Joined
Oct 22, 2007
Messages
8
A friend has the motor above and would like to know the rated rpm and standard prop pitch and diameter so we can start somewhere near correct to prop it. He runs it on a 14 ft open fish boat with a semi flat bottom.

Thanks in advance.

Pete
 

Scaaty

Vice Admiral
Joined
May 31, 2004
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5,180
Re: 1954 Johnson Seahorse 10 hp data

I really don't think you have much choice in props but the one it came with OEM...
 

wbeaton

Commander
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Jul 30, 2006
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2,332
Re: 1954 Johnson Seahorse 10 hp data

Stock prop is 9x8 three blade. I'd stick with it. I use 24:1 with synthetic oil.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: 1954 Johnson Seahorse 10 hp data

10hp at 4,000 rpm. 9 X 8 prop pretty much standard unless running a big
load all the time or really heavy boat.These motors are expected to be working hard do to their relatively small output.
 

samo_ott

Vice Admiral
Joined
Jun 18, 2006
Messages
5,125
Re: 1954 Johnson Seahorse 10 hp data

I just got a line on buying one of these. The guy says it's in mint shape and hasn't been run since the 50's and the original paint is still on the transom screws! Can't wait to see it and if that's true. Should look like this beaut:

old-omc.de/j_1954/seite_08_11.jpg
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: 1954 Johnson Seahorse 10 hp data

That is a model QD-15.

Fuel mix is 24:1 using TC-WX outboard oil per 1964 Johnson Service Manual (covered all Johnson engines up to 1964). The 16:1 was when using 30W motor oil.

Power rating is at 4000rpm, but may run 4500 at WOT. I would run it at 4000.

Spark plugs are Champion J6C gapped at .030", points are set at .020".
 
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