Blower: Can't Turn Engine Off

A lever actuates the ignition switch on your leaf blower. When the ignition switch is set to the “on” or “run” position, the circuit that the switch controls is open. In other words, no current is flowing through the switch. To turn the engine off, the ignition switch is set to off or a kill switch is depressed. This creates a circuit from the ignition coil straight to engine ground. As a result, the spark plug no longer fires and the engine shuts off. If the lever on your leaf blower is damaged or malfunctioning, it will not allow the circuit to be created, and the engine will not turn off. If the lever becomes damaged or malfunctions during operation, you will not be able to turn off the engine. A damaged lever may also result in your engine being unable to turn on, if the damage occurs while the machine is not running.

The ignition switch is turned on or off to control the ignition circuit. However, if your engine relies on the ignition switch to complete the circuit and shut down the engine, a damaged switch can result in the engine continuing to run. In either setup, the switch would be the culprit. If the switch is an on/off type it is creating a circuit to ground when it is off. The circuit opens when it is switched on, allowing the current to flow to the spark plug. In a kill switch setup, the switch normally does not create a circuit which allows the engine to start and run. When you want to shut the engine off, the switch is depressed and held. This creates a circuit to ground which shuts off the engine.

The wire harness in your leaf blower houses the wires that connect the ignition switch to the ignition coil, and protects them from being damaged. If the wire harness is faulty, it can result in loose or damaged wires. This in turn disrupts the function of the ignition switch, and does not allow the engine to turn off. If the damage is done to the wire harness while the blower is not operating, it will result in the engine being unable to turn on.

Many electric blowers have trigger switches that could cause the motor to stay on. The trigger in your leaf blower can also be known as the throttle control lever, and controls the speed at which the blower is blowing air. If the trigger on your leaf blower becomes damaged or stuck, it will affect your ability to control the power of the blower. This will keep you from being able to turn off the blower engine.

Some blower switches could be activated by a part called a rod. This completes or interrupts the ignition circuit, turning the engine on or off. Like the function of the lever above, if the rod is damaged or malfunctioning, it could result in the engine becoming unable to turn off.

The ignition module in your leaf blower is also known as the ignition coil. The ignition coil or module works with the fly wheel to induce electricity and subsequently sends voltage to the spark plug. Often when there is a malfunction in the ignition module, it is a result of a faulty or damaged wire or a bad connection. If the wire mounting tab for the kill wire broke off the ignition coil, you will not be able to turn off the engine. As you will be working near the engine of the leaf blower for this repair, be sure to disconnect the spark plug and empty the fuel tank before you begin the job.