It keeps absorbing the fuel. 75 Fuel
The item id for Kuwait Palm Gas Can in unturned is 5557. You can use this ID with the commands below to spawn the item, give it to a player or buy it on a modded economy server.
Useable: Fuel
Size_X: 2
Size_Y: 2
Size_Z: 0.6
Fuel: 75
Blueprints: 1
Blueprint_0_Type: Utilities
Blueprint_0_Supply_0_ID: 5501
Blueprint_0_Supply_0_Amount: 4
Blueprint_0_Build: 27