Is this low compression 3 hp Johnson JW 10

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Is this low compression 3 hp Johnson JW 10

Did you ever actually check the spark to see if it would jump the 5/16" or 1/4 " open air gap ?
 

cajuncook1

Chief Petty Officer
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Sep 3, 2009
Messages
559
Re: Is this low compression 3 hp Johnson JW 10

Here is a nice little link that has some decent information about your motor. It should have a parts breakdown for your motor.

http://outboard-boat-motor-repair.c... Johnson 3 HP 1952-1967 Tune-Up Procedure.htm


http://outboard-boat-motor-repair.c...Johnson 3 HP 1952-1967 Tune-Up Parts List.htm

Do yourself a favor, get new coils, points, and condensers. Don't for get the oil wick as well. You mess with old coils or incorrect coils then you will find yourself in the middle of no where with a motor that runs inconsistent or not at all. Messing with questionable coils is just asking for trouble and hell of a lot of aggravation!!

Just rebuilt a 1957 3hp Evinrude couple of months ago and she idle slow and smooth. 75psi each cylinder is good and your motor will run fine. You can do a seafoam treatment after you get your motor running and it may increase your psi a few points.

Here is a link by Joe Reeves that detail how to adjust your carb

http://forums.iboats.com/showthread.php?t=167352

Good luck with your motor....you have a well built motor.
 

Tim Frank

Vice Admiral
Joined
Jul 29, 2008
Messages
5,346
Re: Is this low compression 3 hp Johnson JW 10

Did you ever actually check the spark to see if it would jump the 5/16" or 1/4 " open air gap ?

He seems to be ignoring that question....but he did check by "eyeball". :):rolleyes:
If it truly does have "good spark" as per his first post, I am not sure why he is messing around with the coils.
 

fishon71

Chief Petty Officer
Joined
Jul 21, 2002
Messages
575
Re: Is this low compression 3 hp Johnson JW 10

No I didn't measure but found the coils to be all cracked and broken - most likely leaking
 

kbait

Commander
Joined
Nov 13, 2007
Messages
2,471
Re: Is this low compression 3 hp Johnson JW 10

If the coils you have laying around look the same, and aren't cracked, give 'em a try.. Also, make sure you file your points to shiny and no pits before setting at .020", and cut 1/4" off the plug wire ends where they fit to the coils so you get a positive connection.
 

fishon71

Chief Petty Officer
Joined
Jul 21, 2002
Messages
575
Re: Is this low compression 3 hp Johnson JW 10

Thanks, I'll get on this soon and will report
 

fishon71

Chief Petty Officer
Joined
Jul 21, 2002
Messages
575
Re: Is this low compression 3 hp Johnson JW 10

Put in those used coils in, cleaned things up a bit & adjusted the points, now it runs like a swiss watch. I love how these old 2 cyls run so smooth - thanks for the help
 
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