What is the maximum diameter for a fuel filler inlet restrictor?

The maximum diameter for a fuel filler inlet restrictor is 0.950 inch. This specification is critical for ensuring that the fuel filler neck is properly designed to prevent the introduction of non-compliant fuel types and to manage vapor emissions effectively. The restrictor acts as a safeguard, allowing the appropriate fuel nozzle to fit while preventing larger nozzles that may lead to misuse or contamination. Having standardized dimensions for these components helps maintain safety standards and environmental protections in fuel systems. Choosing a diameter larger than the specified limit could compromise these safeguards and lead to compliance issues, making the 0.950 inch diameter the correct answer.