How to Troubleshoot a Toro 450 GTS2 Mower That Won't Start

Park the mower on a flat level surface. Try to start the engine using normal starting procedures (using the correct amount of choke and primer depending on the outside temperature). Verify that the rewind rope pulls normally. If it does not pull normally, disconnect the spark plug wire from the spark plug then turn the mower onto it's side and remove all debris that may be impeding the cutting blade emotion.

Rotate the cutting blade by hand several times through a complete blade evolution (360 degrees). Set the mower back onto it's wheels and reattach the spark plug wire. Try to start the engine again using normal starting procedures. Replace the rewind rope starter rope if it still does not pull normally. If the starter rope pulls normally, but the engine does not start after three or four pulls of the starter rope, continue with troubleshooting procedures.

Check that the gas tank is full. Add fresh gasoline if the gas level is more than 1 inch below the filler neck. If the gas is left over from the prior mowing season, drain the gas tank (turn mower onto it's side briefly) and refill with fresh gas. Try to start the engine using normal procedures. If the engine does not start after three or four pulls of the starter rope, continue with troubleshooting procedures.

Pull the starter rope three to five times. Remove the spark plug with a spark plug wrench and check it for wetness (sign of liquid gasoline being present). If the tip of the spark plug is moist, then the combustion chamber is getting fuel. Allow the mower to sit for two hours with the spark plug out to dry out the combustion chamber. If the spark plug was completely dry, remove the fuel line that runs from the fuel tank to the carburetor and blow it out to remove any debris that are clogging the line. Reinstall the fuel line.

Install a new spark plug, and tighten with a spark plug wrench. Attach the spark plug wire. Try to start the engine again, but this time without applying any choke or primer. If all fuel systems and other engine systems are good, the engine will clear itself and start after three pulls of the rope. If the engine does not start after three or four pulls of the starter rope, continue with troubleshooting procedures.

Remove the air cleaner, and install a new air cleaner. Try to start the engine again without applying any choke or primer. If the engine does not start after three or four pulls of the starter rope, then the engine needs more than routine maintenance to become operational again.