Symptoms
- Engine keeps running after switch is moved to off
- Trigger release doesn't stop the engine
- Have to choke the engine or remove the fuel line to stop it
- Switch feels loose or doesn't click firmly
Likely causes
- CommonFaulty ignition kill switchA worn or corroded switch may not properly ground the ignition to stop the spark.
- CommonBroken or disconnected ground wireThe wire from the switch to the engine can break or come loose.
- PossibleStuck throttle linkageA stuck throttle can keep the engine revved even if ignition is cut.
What to do
- If the engine won't stop, use the choke to cut off air supply as an emergency stop method, or disconnect the spark plug wire with a tool if safely reachable.
- Once stopped, inspect the kill switch and its wiring for looseness, corrosion, or breaks.
- Clean corroded contacts or reconnect any loose wire terminals.
- Test the switch continuity with a multimeter if you're comfortable doing so.
- Check the throttle cable and linkage for sticking that could be keeping the engine revved.
- Replace a faulty switch with the correct replacement part for your model.
- If the wiring and switch test fine but the issue continues, a small-engine shop can diagnose the ignition module.
Tools and parts
- Multimeter
- Basic wrench set
Ignition kill switchSearch: “small engine kill switch replacement”
When to call a pro
A small-engine shop can test and replace the ignition module if the switch and wiring aren't the cause.
Safety
Use caution
If the engine won't shut off, keep hands and clothing away from moving parts while using the choke or disconnecting the spark plug wire to stop it.