Sam, just to clear some things below up and add more info, the mag DOES NOT have what is actually any timing "advance" (it doesn't mechanically "advance" the time over 200 RPM). When she's running over around 200 RPM its timing is determined by 1) The Drive Cup used,,,,,,,2) Points Gap,,,,,,,,,3) Rotation/position of mag in the governor case,,,,,,,,,4) A few other factors. Its does NOT advance the timing and normal run timing is set, but the timing is RETARDED for starting via the impulse assembly.
However, the mags impulse mechanism PERFORMS THE RETARD FUNCTION so that less then 200 RPM due to the lack of sufficient centrifugal force the impulse mechanism engages and if the adjustment is at say a 20 degree LAG ANGLE (Means how much the start timing lags behind the normal run timing) when its engaged she will fire 20 degrees RETARDED from where the normal run timing occurs. IE start at TDC (20 degrees RETARDED), normally run at 20 BTDC. NO ADVANCE MECHANISM only a retard mechanism (impulse assembly)
Soooooooooooo the mag DOES NOT advance the timing at run RPM. However the impulse mechanism causes it to RETARD the timing when you're starting it, otherwise she would kick back if she sparked before the piston is at TDC.
Lag Angle is how much the start/impulse timing LAGS the run timing. To enable it to start and NOT kick back the impulse mechanism retards the timing slower then what she normally runs at.
Hope this helps
For best hand crank starting you want the start/impulse timing at TDC. Too fast she kicks back, too slow shes harder to start.
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