Engine needs to be throttled down enough for the safety-switch to be off/ungrounded it junctions on an isolated lower terminal of the cut out sw then to the solenoid opposite the ign terminal. It's to keep the engine from cranking at too high throttle. There is internal shift linkage to keep the throttle from opening too far, if in neutral and a little faster in reverse. WOT is only available in forward.
The safety sw is mounted under the flywheel and is ajusted during synchronization. (Get a book)
Sometimes no crank is from a bad solenoid or bad battery or ground connection...