It runs out of fuel, and Squidward kicks the front bumper. It instantly fills up again with gas and goes down the road, never to be seen again. Before they leave on the delivery, Squidward and SpongeBob check the tire pressure, antenna, bumper, and bumper sticker (which reads 'I Brake for Sea Urchins'). Its steering wheel is on the right side of the car, minorly suggesting it may have come from Australia or Great Britain.
The boatmobile gets less and less detailed as the episode ("Pizza Delivery") continues.