I have no spark . I have the seat switch bypassed .

Hi,
Depends on the exact engine. Could have an igniter(a small silver metal piece near the dipstick.) There were three versions of this engine about. Sometimes the coil and igniter both go. The last version of the engine had it built into the coil and that is the way to go if possible. You tell them apart by the flywheel part number. The first engines had a different flywheel and the other two had the same flywheel but one had two pieces to the ignition and the other last one had a single piece.
Peace,
Clarke