Small engine NGK spark plug (BPR6ES). If the engine does not start, the spark plug may be defective. The spark plug should be replaced periodically during regular maintenance.
Honda flywheel key. The flywheel key aligns the flywheel in the correct position on the crankshaft. If the engine stops suddenly due to hitting a hard object, the flywheel key shears in half to prevent damage to the engine. If the flywheel key is broken, the engine won't start.
Ignition coil assembly