This locking fuel filler cap seals the tank opening on the host tractor, preventing fuel spillage and contamination during operation. It sits at the fill port of the fuel system, where a secure closure is needed to keep debris out of the supply line. The cap includes a set of keys, allowing it to be locked in place to deter unauthorized access or tampering. A worn or missing seal on the cap can allow air ingress, which may cause fuel starvation or erratic engine performance. On reinstallation, ensure the cap is fully seated and locked to maintain a proper seal.