Riding lawnmower safety is a significant concern to mower manufacturers. Many built-in safety features reduce the operator's chances of injury. Knowledge of the riding mower's safety features helps avoid engine starting problems.
Set and lock the parking brake before starting the mower. The parking brake prevents the mower from jumping forward if the mower is in gear when the engine starts. A safety switch mounts near the base of the parking brake lever. With the brake fully engaged, the switch closes and allows current to pass through it to the starter.
The power take-off (PTO) must be off for the riding mower to start. The additional load on the engine with the blades engaged can prevent the engine from starting. The PTO is the lever near the steering wheel for engaging the cutting blades. A switch for the PTO lever mounts under the dash of the mower. With the PTO in the off position, the switch allows current to the starter.
If the mower engine is cold, advance the throttle to its fully open position to engage the throttle choke. The choke allows more gas than air into the carburetor for a quicker start. However, if the engine is already warm, advance the throttle to the normal run position. The choke position will flood the engine with gas and prevent it from starting. In that case, wait 30 minutes to an hour for the excess gas to evaporate before attempting to start.
A switch in the seat of the mower works in conjunction with the other safety devices. Its purpose is to sense if the operator is in the seat. If the mower were to tip over or the operator fell out of the seat, the switch would shut off the mower. Likewise, the operator must be firmly in the seat for the mower to start. The riding mower will idle with the parking brake set. The engine will not idle, however, with the PTO engaged and no weight in the seat.
A riding mower ignition switch typically has four positions: off, run, start and accessory. To start the mower, turn the switch fully to the right to engage the starter. The ignition switch will return to the run position when it is released. Do not hold the ignition switch in the start position for more than 10 seconds at a time. Doing so can damage the starter and ignition circuit.