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1960s-70s Johnson only spark on one cylinder

D

dtown

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I let my motor sit after I spun a prop I got a new prop and tried starting motor but it had no spark, I cleaned the inside of the flywheel and the points, the back of the the points the are close to the crank shaft were pretty rusty after awhile I got spark to one cylinder but not the other
 
It’s a 1966 Johnson 9.5, mq-12A, when I put the test light on it lights up, it also shocked me pretty good but as soon as I put the plug on it doesn’t spark, tried different plug and also tried different spark plug cap, I cleaned the points and set them to 20 thousands with the scrubber at the “top” mark
 
All of those original coils cracked.---Are the coils new replacements on your motor?----Pictures?----A good magneto on those can jump a gap of 5/16" on a test device.
 
I don’t believe it’s the coil, I took the coils off and switched them around to see if the problem followed to the other side and it didn’t still that one cylinder isn’t jumping spark on the plug but hits the test light
 
I ordered the tune up kit with points n condensers, I’m gonna take the mag plate off n inspect the wires further
 
Wires tend to crack / leak at the sharp bend coming down from the plate.----Used to find that with the wonderful ----MERC-O-TRONIC---Magneto analyzer.
 
After messing around with the armature plate and cleaning the points again I got spark to both cylinders put motor won’t start only back fire every other couple pulls did I mess something up when I pulled the throttle lever thingy apart
 
Update I had the wires backwards lol so definitely dirty points, I will still replace them when they come in, thank you guys for the tips and information! I wouldn’t have had the motivation to keep troubleshooting it without more ideas
 
Welcome. When you install the points, put a tiny amount of grease on the points pivot shaft. Be certain that your spark coils are set to the farthest inward edge of the mounting posts. You will notice the taper right at the top of the post. Coils are cheap and will be around for many decades, so if the flywheel weights have been rubbing the coils, I would change them out anyway. A new good quality coil will give you enormous spark. Check compression and you will find out how many fishing trips are left in that little gal. Non oxy fuel only. They may not be the fastest 10 hp on the lake/river....but likely the most reliable.
Tim in Duluth
 
I wouldn't either, ha....unless it had another motor like an Evinrude fisherman setting right next to it. Good thought, brother.
 
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They have a host of possible illnesses, most from attempts to repair them carelessly, but great features make them one of my favorites..Ethanol fuel is terrible on crank seals....seems like the material is quality rubber....ha! I can tell by the way the seals will turn black on your little finger.
Thanks for picking up the slack here, Droid. Your help is truly appreciated....good job, brother.

.
 
When I had my shop we were very thankful for ethonal fuels.
That being said it DOES NOT go in any of my boats, snowmobile or lawn equipment.

Bad fuel, cheap oil & failure to replace impeller are what do most 2 cycles in.
 
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