Reply To: 1955 Johnson 10 HP QD-16, no Spark

[Don]

All good suggestions.   And yes, there is a specific “air gap” that the coils must be set to.  There is a special tool/ring to set this air gap, but I’m sure you don’t have that.  So, it is usually “close enough” to line up the coil laminations with the machined marks just below the coil laminations on the mag plate.  The coil laminations will hit the flywheel and cause damage if the coils are set out too far, and the magnetic fields won’t be strong enough to produce proper voltage if the coils are set out too far from the flywheel magnets.

These engines are a bit of a challenge to set point gap with the crazy spring/seal set up under the point cam.  You must be very careful when reinstalling the flywheel, oftentimes the cam will come down on top of one/both of the point arm rubbing blocks, forcing it down can damage the points.  Once the flywheel is installed and snugged down slightly, you could always recheck point gap by removing the flywheel cover and checking the gaps when the open flywheel window is over each set of points.  This brings me to another possible issue.  Improper flywheel torquing could have led to the flywheel key shearing when you tried to start the engine.  Once the flywheel key is sheared, even slightly, you will have no spark on either cylinder.

And like Mumbles pointed out, it is easy to connect the coil primary leads to the wrong set of points, which would lead to no spark also.  And yes, new points need to be cleaned, there may be a slight coating on them which is enough to cause an issue.