I have had nothing but trouble out my JR 9100 series servos. I have sent them back so many times over the past 2 years (3times)that they have said I no longer have warranty. This season I switched to Hitec 7940th for throttle and its awesome. Not a single hickup so far and I have had a 5955tg that has been in regular use for 3 years now that still works perfectly.

On a second note run a LIFE pack don't go lipo. IMO LIFE is better and much safer.