On my granddaughters ATA 125 D, when you use the brake (foot or handle), the starter engages. I visually checked for wiring rubbed bare or loose etc. and found nothing suspicious. I also looked at the wiring schematic in the owners manual(chineese writing) , and the troubleshooting chart was no help either. Any help much appreciated.
John

 

Most chinese quads use the brake switch as an interlock to keep the quad from starting up and taking off unexpectedly. The interlock requires that you have the brake applied before the start button will allow you to crank the quad.

It sounds like your starter button may be shorted, or stuck in the "pushed in" state. Thus everytime the brake interlock circuitry is satisfied (i.e. you apply the brakes) the quad engages the starter.

Try unplugging the connector leading to the start button. This may be a connector that goes to a multipurpose left handlebar switch, or to a separate starter button. In any case unplug it, turn on the ignition switch, step on the rear brake, and see if the starter motor turns (it shouldn't).

 

Thank You for the help Lynn. I'll give that a try.