I've got a 12R XS in my new R40 and I'm having a hell of a time getting the thing started. Seems that the flywheel always wants to get stuck at TDC and I've really gotta put some force onto the flywheel it to get it to spin down to the bottom of the stroke. I am using 2 1500Mah 7.2v batteries in my starter box, and am wondering if I need more juice than that..and if it would be better to upgrade to a 12v GelCell battery for that extra oomph....any help would be greatly appreciated as I'm becoming VERY frustrated with this whole starterbox engine only experience.