Sounds like a power problem. A better battery/connectors will solve that problem. In the mean time you can change the settings using the PC link software from Castle Link. You can lower the timing of the motor and change the punch control so that the system doesn't draw as much amps, and this will help stop the stuttering on the start. I am running the Mamba 7700 system with a good 6cell pack and it works fine. So a lipo or 7 cell would be best, you don't absolutely need it. A good 6cell will do the trick.