You did have to tune them , adjust the mixture. The throttle was just a rotating sleeve on the exhust. No real carb. To start them you fueled them up, hooked up a battery to the glow plug, and spun the rear tire by hand.
If you had a very long real flat place to run it, and a very long bit of fishing line it would go like hell. Not sure of the scale speed, but prob. almost as fast as real Dragsters of the time. Tires never stopped spinning. Perhaps a large rear wing would have helped. But is was a front engine type, they should have had a Garlits model. Much safer for driver.