Johnson QD -16 top cylinder misfire

[alwayslearning]

Good morning all. I have a QD with a top cylinder dead. The strange thing is it has spark and will fire when I hold the boot about 1/4 inch away from the plug. I have tried over and under setting the points, new plugs. Things I plan on checking are compression and rebuilding the stator in case there is a minor crack in the ignition wire. I am only guessing though and grasping at straws. Any sage advice that may save me the last remaining hair on my head?

 

[AlTn]

Re: Johnson QD -16 top cylinder misfire

I'll venture that your "minor crack" theory is plausible...holding the boot in position is allowing a path for the spark that is not there with the boot attached to the plug...depending on how deteriorated the terminal end of the plug wire has become, try pulling the plugwire and terminal out of the boot, cutting off 1/2" or so of the plugwire then reattach the terminal and push it back into the boot. If your spark has rerturned this may be all you need to do. I'd follow your impulse to remove the armature plate and repalce the plugwires along with new terminals and boots. The plugwires "screw/twist" onto the spike in the coil. If you just push them onto the spike it make break it. A little wd40 makes removing the terminal end from the boot easier. An "autopsy" of the plugwire will probably reveal a lot of greenish corrision at each end.

 

[kfa4303]

Re: Johnson QD -16 top cylinder misfire

Ditto what AlTn said. if should find the the s'plus wires are green/corroded and you need to replace them, be sure you get copper core wire only, NOT automotive graphite wire. I just got about 6 feet worth for about $3 a foot with some new boots from NAPA, and it made all the difference in the world. Like Altn said, if you do put new wires on, be sure you twist them on to the needle post of the coil, rather than just poking them on there. The coils and or condensers may be on the fritz too. You can swap them to see if you get spark in the upper and not in the lower. Good luck. Keep us posted.

P.S.
Just took my QD-22 out today after months of tinkering and........it worked!