Re: Johnson 6 missing or backfiring at wot?
If what you're experiencing is a sharp instantaneous momentarily miss, that would be an ignition type miss.
Fouled plugs, wrong plugs, failing condenser, burnt and/or misadjusted points, loose armature plate, etc.
(Magneto Armature Plate)
(J. Reeves)
If the armature plate has a a loose fitting, wobbling motion (the plate that the points, coils etc are attached to), it is usually caused by a slightly worn support ring. This allows the point setting to change erratically as the armature plate turns.
The cure is to remove the armature plate so that the support which is attached to the powerhead with 4 screws is visible. Then, with a screwdriver and hammer, or some tool of your choosing, and looking straight down at the support ring, make an indentation at what would be called the 12, 3, 6, and 9 O'clock positions. Install the armature plate and check for a smooth turning wobble free movement.
You may need to do that procedure a few times to obtain the proper fit (not too tight, not too loose), but it's worth the effort.
Use a small amount of anti corrosive grease between the aluminum ring and the brass support plate and also on the brass bushing of the armature plate when all is well.
