Kohler part no. 25 313 01-S, 2531301-S. See photos of part. This is the rubber bushing part that creates a tight seal between the fuel tank outlet hole and fuel shut off valve. for hole in tank, 8.8mm hole dia.
Fuel Tank Valve Seal Grommet Bushing Set, Compatible with Tecumseh 33679 735-0149 935-0149 Simplicity Allis Chalmers 1654930 Snapper Kees Wheel Horse Models, 5 Pack
Fuel Tank Valve Seal Grommet Bushing For Stiga 1134-3225-01, 337260151/0
Fuel Tank Valve Seal Grommet Bushing, For Kohler Engine 25 313 01-S, 2531301-S
Fuel Tank Valve Seal Grommet Bushing For Toro 104047, 46-6560, E513645, 1-513645
Fuel Tank Bushing Grommet Kit Pack of 5 for Tractor Lawn Mower Generator