Well duh, empty the tank!

From Red Ball’s website -

Items movers won’t move: Power Equipment with Fuel.

The list of things movers won’t move also includes power equipment with fuel in the tank. This includes motorcycles, lawn mowers, weed eaters, and so forth. Before movers will move these items, you must drain the fuel or run the item(s) until the fuel reserve is completely empty. Be sure to do this at least 24 hours before loading.