Adding to what CG said, when I have a weak starter battery and am having trouble getting it to turn over, I will actually move the prop just a bit further, so that it is "hung up" at TDC of the compression stroke. I've found this gives even more of a running start. Make sure when you do this that you either have the glow ignitor off or that you have a firm grip on the prop, as it the engine may fire and whack you in the hand. Also, as others said, make sure you have a good match between spinner and starter insert. The starter you mentioned should have no problem with a full charge on the battery.