Engine runs with Mags off

[Mike Busutil]

If you do a normal start up, but turn off the mag while leaving the starter switch on, the engine will remain running

 

I notice a slight raise in MP and a slight drop in rpm when the mags are turned off, but the engine remains running nearly 100% normal

 

With the engine running while the mags are off and the starter switch on, the max rpm is 2400 with a max MP of 52

 

Idle rpm is 550 and 1900 MP

 

The starter does not seem to overheat or burnout while doing this

Edited October 6, 2013 by Mike Busutil

[sobek]

While the starter switch is engaged, there is an additional booster coil being switched into the spark plug circuit that is charged via the battery and operated with a mechanical breaker to initiate the step response to ensure a spark while the engine is turning too slow for the mags to work. This is expected behaviour and not a bug. Also, the impedance of an electrical motor not having to supply its full torque is significantly higher, which means that there is less current through the motor and therefore less thermal loss, therefore the starter is much less likely to burn through when the engine is already firing.

[Mike Busutil]

Roger that, thank's Sobek.