The E-Z Start system,
Is great and will last a long time but, maybe not with the 2.5?? I would use some nitro in the range that is supposed to be run through that engine like 20%! Even if it is airplane fuel it should still be the right % for the engine! Your one-way barring could be worn out and not catching the starter shaft?? If you can turn the one-way by hand on the shaft without it catching it is worn out!