I am building a dmr and im usuing an m150 spring. I shimmed the gearbox perfectly and everything. I am usuing an echo 1 high torque motor with an 11.1 lipo. Now here is the problem: The gun cycles about 3 times, but on the fouth time the gearboxlocks up and leaves the piston stuck back, when i pull the trigger the motor heats up and starts to smoke! It will not pull the spring anymore! How can i fix this! I know this motor can pull the spring but it just keeps refusing!