Re: low tension magneto question

[rudderless]

I have been working on these systems for years. Back in 1970 or so most snowmobiles had this system.

There is a thing called the right hand rule. Make a thumbs up sign with your right hand. The thumb points in the direction of DC current flow in a wire, and your fingers point in the direction of the magnetic flux. Point your thumb down and the flux travels in the other direction. Keep this in mind.

The driver coil is not center tapped or grounded on either end. The flywheel is NS then SN so the current can reverse direction in the driver coil for each cylinder. Why so one might ask. The spark should jump from the center electode to the ground. In the 9.9/15 configuration if wheel was NS,NS the spark would jump from the ground to the center on one cylinder, causing fast erosion of the ground electrode. Right hand rule rules.

Okay, points close on one end of the driver while cap and points are in parallel with the coil on the other end of the driver. The points on the cap end are open, not in the circuit at this time. Magnets cause current flow, energizing the driver coil, spark coil and cap. Points open at highest mag flux causing the flux to collapse into the secondary winding in the spark coil, causing the spark. The degausing cap keeps energy in coil from bleeding out through the point spark as they open. Without the cap the energy would follow out with the point arc, causing weak spark or none at all. The cap discharges keeping the potential about even on both sides of the points as the points open. When the cap has discharged the flux stored in the iron is kept strong and collapses into the secondary winding causing the spark.

Things switch for the other cylinder. Points that were open during other cycle are now closed and other points are now open, out of the circuit.The other magnets are switched causing current to flow in the other direction, towards the other coil.

The fixture you have times the magnets with the point opening for strong mag flux. There is no way for you to have it 180 out. My 1976 factory service manual explains this pretty well. Not sure if the other years have this explanation. Don’t go by wire colors on used stuff, could have been screwed with in the past.

There is my first post on this forum..hope it went well.