When I arm the drone the motors start rotating at some throttle percentage may be (7%) and the drone will automatically disarm after 14sec and again the process repeats after I arm the drone.

After some research, I found that this can be controlled by the parameters like MOT_SPIN_ARMED and THR_MIN but these are not available in the standard parameters list like in the video I saw.

I tried manually resetting the values like setting MOT_SPIN_ARMED to 0 and THR_MIN to 30 then the motors not started spinning when armed but when the throttle is given all motors are not in sync one motor starts at a different throttle level. I also performed all-ESC calibration and everything goes fine. But the motor yet picks up at a different speed. But when I reset the parameters the motors are all in sync as expected.

I'm not sure why I can't find the MOT_SPIN_ARMED in standard params. I'm really troubling with this issue any help is highly appreciated.

Firmware: Copter stable v3.2.1 Arducopter version: 2.8