Home › Forum › Ask A Member › How Important is OMC Ignition Timing? › Re: How Important is OMC Ignition Timing?
In a flywheel magneto system (as in OBMs) there are two ignition events which must be correctly timed. Event #1, is the peak flux through the ignition coil, which is the point where the spark is the strongest. Event #2 is the correct point where the plugs must fire the cylinder(s). If you’ve ever set timing on a car, truck engine, you are setting event #2 – that’s "the timing" we all know of.
Think of #1 as an acceptable range and #2 as a very specific instant within that range. Event #1’s range cannot be adjusted, it’s a function of the relationship between the rotor magnet(s) and the ignition coil(s) – and that’s fixed at the factory by the placement of coils, magnets and flywheel keyways.
Event #2 can be adjusted by varying the points gap – so it’s field-adjustable. We have to trust the factory engineers that the correct point for event #2 (which we will set by varying gap) will fall within the desired range of event #1.. and in any properly executed design, that’s just how it works out!