Precision fuel metering check valve cartridge

A check and flow metering cartridge valve having two flow restriction zones, each zone being disposed adjacent a respective end of a valve chamber containing a check valve member, the zones being serially encountered by flow through the valve, the restriction of the restriction zones together being a majority of the total flow restriction in the valve, each restriction zone producing at least 26% of a total flow restriction to flow through the valve, the restriction zones maintaining back pressure in the valve chamber when the check valve member is unseated thereby providing damping of the check valve member, the restriction zones comprising a primary and a secondary zone, the primary restriction zone producing 84 to 99% of the total flow restriction and the secondary restriction zone producing 26% to 40% of the total flow restriction and a compression spring in the chamber arranged to bias the check valve member against a seat, the chamber and an outlet being arranged so that for the most part flow through coils of the spring is avoided.