Here are some possible steps you can take to troubleshoot why your Craftsman riding mower model 917.275684 will not start:
Check the battery. Ensure the battery is fully charged and properly connected. Clean the battery terminals if they are corroded.
Check the fuel level. Ensure the fuel tank is full and that the fuel lines are clear.
Check the spark plug. Remove the spark plug and inspect it for damage or wear. Replace the spark plug if needed.
Check the oil level. Ensure the oil level is full and that the oil filter is clean.
Check the air filter. Clean or replace the air filter if it is dirty.
Check the throttle control. Ensure the throttle control is in the "START" position.
Check the parking brake. Ensure the parking brake is disengaged, or the lawnmower will not start.
Try to start the mower. Turn the key to the "START" position and hold it there for a few seconds. If the mower does not start, release the key and wait a few seconds before trying again.
If your Craftsman riding mower still won't start after following these steps, it's time to schedule a service appointment with an authorized Craftsman dealer.