1999 Johnson 2 stroke primer issues

Chuck Gibson

Petty Officer 2nd Class
Joined
Apr 13, 2005
Messages
123
I have recently bought a boat with a Johnson 50 hp 2 cycle motor. It has been sitting in storage for years. The gas was extreamly nasty but after flushing the lines and rebuilding the carbs, it has fired up.
I know that the primer needs to at least be rebuilt due to gas leaking out of it from the switch "o" ring and the red manual switch is cracked. My question is testing it to see if the solinoid is working. I can hear no audible click when the key is pressed in. I pulled it off and ohms tested between the purple wire and ground wire. It has zero resistance. I took the next step and tested the voltage between the purple wire leading to the primer and ground. When the key is depressed, it is NOT showing voltage. Should this not show 12 volts?
Thank you in advance for giving me an education!
 

guy48065

Chief Petty Officer
Joined
Aug 31, 2008
Messages
444
If by "zero resistance" you mean infinite resistance--your primer solenoid is burned out. Pretty cheap replacement.
IF you mean zero ohms it's shorted out. You still need to replace it--AND you need to find the blown fuse or burnt wire that feeds the 12V from the ignition switch plunger to the purple wire.
 

Chuck Gibson

Petty Officer 2nd Class
Joined
Apr 13, 2005
Messages
123
Hopefully by this next weekend I will be able to trace that power problem..
Thanks for your help. I will get back on here to give my results!
 

Chuck Gibson

Petty Officer 2nd Class
Joined
Apr 13, 2005
Messages
123
Thinking about the primer power problem the thought crossed my mind that the primer would have no need to be energized unless the moter was actually turning trying to start. I was pushing the key in without turning it and getting no voltage. After experimenting with it for a few minutes I found that when the key was actually in the start position with the engine turning over I was getting .3 - .5 volts going to the primer.
How many volts does it take to activate the primer.
I would have assumed it would take 12v.
Thanks again!
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
37,847
It is a 12 volt primer valve.----Key is to be pushed in while cranking it over.
 

Crosbyman

Vice Admiral
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Nov 5, 2006
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5,450
find the wire on the primer.... backtrack to the switch find the same wire ...

if the switch puts out 12v you should have 12v at the other end of the wire on the primer if not the wire is open or connections are oxydized .

a grounded wire would cause a blown fuse
 

dingbat

Supreme Mariner
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Nov 20, 2001
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16,083
FWIW: Had a similar issue last fall. Turned out to be a bad key switch.
 

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,450
same basics....

no 12v at the key... primer won't work
12v at the key... primer works if functional and.... the wiring is ok
 

Chuck Gibson

Petty Officer 2nd Class
Joined
Apr 13, 2005
Messages
123
You guys have given me some good stuff to check out. Hopefully this weekend I can go after it. You know how it is... my truck has just started acting up... GRRRRRR! lol
 
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