Anyone know the exact dimensions (width, ID, or OD) of the fuel tank O ring that goes to stop the leakages of fuel tank?

I want to test the scooter fuel pump. For that, I'm using a cylinder type tank (Glass). but, the problem is there are leakages on the tank (Bottom and up). That's why I'm thinking to use O-Ring to rectify the leakage problem. Any suggestions or information about this tank and O-Ring.
Fuel type _ 92 (gasoline)

Thanks, Advance