Tires - If your karts are spinning on the track or not moving -- check the placement of the black tires. The soft rubber tires need to be on the back wheels of the car this allows the karts to gain traction on the track. Karts may spin out frequently - clean rear tires with sticky tape.
Hubs - The hubs are "snap" fit into place on the hubs and the fit is firm. Be sure you have firmly pushed the hub onto the axle so you feel a snap. If you are having difficulty, try turning the motor on its side to attach the hub -- remember to press firmly.
Kart shells - The colorful Kart shell (body) should snap into place on the motor with clearance for the wheels to turn. Center the Kart shell over the motor and press down then slide back until you feel it snap into place.
Batteries - Karts with fresh batteries tend to run tend to run at their maximum speed and may sometimes run off the track.
Battery case - To access the batteries in your Kart, unscrew the cover and slide it back about ¼ inch before lifting up to remove the cover.
Kart Speed - Drop in Kart speed may be noticed after 15 - 20 minutes of continuous play, if this happens turn motor off and allow to rest for 5+ minutes in order for batteries to re-energize.
During heavy continuous play, or if motor/batteries feel very warm, allow the Karts/Batteries a 5 minute rest (turning motor off) to allow batteries to cool and recover.
Motor switch - If you have difficulty moving the switch to the ON position, turn the rear wheels and try the switch again.
Specific Building Help for Bowsers Castle Ultimate Building Set #38437
Parts List error - 2 Goombas (brown pieces with angry faces) pictured in Parts List are not included in the build and the pieces are not included as part of the set.
Additional Tips to help get your motors functioning properly:
Mario Kart Wii battery case - Need to change the batteries? Slide and lift the kart body to access the battery cover on the motor. After unscrewing the lid, slide the cover toward the front axle (the smaller side of the motor) and then lift to remove the cover and access the battery compartment. After changing the batteries just pop the kart body back in place and you are ready to roll!
Karts on the Track - If your karts are spinning on the track and not really going anywhere you need to check the tires. Motorized karts have 2 sets of black wheels. The soft, flexible tires go on the back hubs of the kart (the drive wheels) to provide traction on the track. The hard slick tires go on the front hubs to provide stability. Your karts will run much more smoothly this way! (Please note that the Bowser and Standard Kart set function best on the floor and not on the track which is why the set did not come with track)
My Kart won't move?! - If your kart won't move, check the rear wheels. Your kart body may not be properly locked in place and touching the rear wheels. To correct this, snap the kart body down onto the motor and then slide it backwards until it snaps into place. This wheel free the rear wheels to spin.
My kart runs too fast and keeps jumping the track - When kart batteries are brand new they can sometimes provide a burst of extra speed for the first few minutes of operation. This can make the karts jump the track. The burst will pass if the motor is allowed to run for a few minutes. After this time the kart should settle into a more normal racing speed.
My Kart just spinning circles on the track - For karts that are meant for the track (the ones with battery operated motors), be sure the soft black tires are on back hubs for traction and the slick hard black tires are in the front wheels of each kart for stability.