I got a gas tank from an RC airplane, and ran the lines as shown, it’s an 11oz tank, that you can quickly refill with the fill bottle:
Here is where the tank goes, very tight fit under the engine cover, you can sorta see here, hard to get a clear view of it.
And once the gas tank was hooked up, it was time to fill it with gas, and fire up the motor. For testing pruposes the engine cover was just set in place. Also note that the twist throttle and kill switch are installed.