1972 johnson 9.5hp will only run with choke out

boomer2001

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Feb 20, 2011
Messages
10
I ahve a 1972 johnson 9.5 it will only run with the choke pulled out, i can cover the carb with fingers to keep it runnin. what can i do or what do i need ot do to fix this.
 

Joe Reeves

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Feb 24, 2002
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Re: 1972 johnson 9.5hp will only run with choke out

Remove, clean, and rebuild the carburetor.
 

kevin11mic

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Oct 12, 2010
Messages
96
Re: 1972 johnson 9.5hp will only run with choke out

Well this means its running lean aka getting to much air. Could need to rebuild the carb and clean it out. Check all your gas connections for leaks. Probably something with the carb
 

boomer2001

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Feb 20, 2011
Messages
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Re: 1972 johnson 9.5hp will only run with choke out

Thanks Joe, Just went out and bought a rebuild kit. Will update tomorrow after i rebuild it.

Ps Do you know where i can find a wiring diagram for a switch box on a mercury 200-20hp 1980. bought it and prev owner had switch box replaced but forgot how to wire it back up.

Thanks

boomer reeves
 

1946Zephyr

Vice Admiral
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Oct 21, 2008
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Re: 1972 johnson 9.5hp will only run with choke out

That's a question you might want to post on the Mercury Forums here. :D
 

F_R

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Jul 7, 2006
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Re: 1972 johnson 9.5hp will only run with choke out

Back to the 9.5 topic, it is a safe bet that the high speed jet (orifice plug) has dirt or gum crud in it, so pay special attention to it when working on your carb. It must be absolutely Clean without a trace of any obstruction in it or you will get the symptoms you describe. On the other hand, do Not be running wires or drills through it. An oversize or scratched orifice is as bad as a dirty one. Actually worse--you can clean dirt out, but you can't put metal back.

May I add that a special screwdriver is required to remove the orifice plug?
 

boomer2001

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Feb 20, 2011
Messages
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Re: 1972 johnson 9.5hp will only run with choke out

rebuilt carb. Lil motor runs like new Thanks to everyone for the help and advise. A+++
 
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