ORIGINAL: mvallyman
I've run into this many times on my Saito 125. I have a low and high idle set up on the Tx and also a kill switch that positions the throttle closed. It seems to be that if the throttle can be open just enough for an idle but also enough that it produces too much compression for the starter to turn it over even with a fully charged battery.
This is an OS 65LA two-stroke a totally different kettle of fish.
With a 4-stroke, closing the throttle makes the engine much easier to turn over it makes virtually no difference with a 2-stroke.