Small engine Champion spark plug (RJ19LM). If the engine does not start, the spark plug may be defective. The spark plug should be replaced periodically during regular maintenance.
Tecumseh ignition coil (also called a lamination). The ignition coil sends voltage to the spark plug while the engine is running. If the ignition coil is defective, the engine may not start.
Champion Spark Plug (RJ17LM)
Tecumseh flywheel key (woodruff 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.