A recoil starter, also known as a pull starter or rewind starter, is a mechanism commonly used to start small engines like those found in lawnmowers, chainsaws, and small generators. It allows you to manually start the engine by pulling a cord, which then engages the engine’s crankshaft to initiate the ignition process. Here’s how a recoil starter typically works:
- Components: A recoil starter consists of several key components:
- Pull Cord: The user pulls on this cord to initiate the starting process.
- Handle: The handle is attached to one end of the pull cord, providing a grip for the user.
- Recoil Spring: A coiled spring is connected to the other end of the pull cord. This spring stores energy when the cord is pulled and releases it to spin the engine’s crankshaft.
- Pulley and Pawl Mechanism: Inside the starter housing, there is a pulley and a pawl mechanism. The pulley is connected to the engine’s crankshaft, while the pawl is a small, spring-loaded lever that engages with the teeth on the pulley.
- Initial Position: When the engine is not running, the pull cord is wound around the pulley, and the pawl engages with the teeth on the pulley. This keeps the cord in place and prevents it from unwinding.
- Starting Process: To start the engine, the user grasps the handle and pulls the cord outward rapidly. This action causes the cord to unwind from the pulley.
- Recoil Spring Action: As the cord is pulled, it also winds up the recoil spring. The energy is stored in the spring during this phase.
- Release of Energy: When the user releases the cord, the recoil spring rapidly unwinds. As it unwinds, it exerts force on the pulley, causing it to spin. This spinning motion is transferred to the engine’s crankshaft.
- Engine Ignition: The spinning crankshaft engages with the engine’s internal components, including the piston and the ignition system. This motion generates the compression and spark necessary to start the engine.
- Pawl Disengagement: As the engine starts running, the crankshaft spins faster than the recoil starter’s pulley. This causes the pawl to disengage from the pulley’s teeth, allowing the pulley to spin freely without turning the engine’s crankshaft.
- Cord Rewinding: With the pawl disengaged and the engine running, the recoil spring begins to rewind the pull cord back onto the pulley. This prepares the starter for the next use.
- Idle Position: Once the cord is fully rewound, the recoil starter returns to its initial idle position, ready for the next pull start.
The recoil starter is a reliable and simple mechanism for starting small engines, offering a manual alternative to electric starters. It’s important to properly maintain and lubricate the recoil starter components to ensure its longevity and reliable operation.