I have two 2-stroke petrol hover mowers; a Flymo contractor L50 and an Allen something. both use identical Techmseh MV100S engines. The Flymo has a setting on the throttle lever which grounds a wire from the magneto to the engine block. This stops the engine.
The Allen has the cable grounded to the engine block to allow it to run (via a dead man switch). Can anybody through light on the purpose of the wire from the magneto which has seemingly opposite effects on seemingly identical engines?