Honda GXV530 Starting Issues

Hi, I have a Hustler Fastrak with a Honda GXV530, i have had issued with starting. I have to rotate the engine a few times by hand while turning the key to get it to start, when it starts it runs great heaps of power. I have installed a new battery and starter motor, still no good. When i turn the key the starter throws out but wont always turn the engine. Any help would be greatly appreciated.