My advice was based on helping the guy get some guidance. And, this is a place that can definitely give guidance. But, owning a manual is pretty solid advice. Coming from a guy who’s pup shredded his revo manual. And, never order a replacement. It would have helped me tremendously on a car...
I don’t know.
Let me give you a solid piece of advice. From a guy that just went through this with an unknown nitro rc. Buy an owners manual. Or, find a schematic for the motor that’s in that car.
You need to learn the differences in your carb needles. And, the factory setting for those...
Reset your throttle linkage to neutral. It sounds like the servo horn needs to be reattached in a different setting.
Unscrew the horn from the servo, turn the car on and let the servo adjust. Reattach the servo horns and see where you are at.
It needs to stay shut until you hit the throttle.