Ariens starter problem

Recently my 46" mower developed an odd starting problem. The starter will no longer take the engine past the compression stroke unless I manually back the engine up to the back side of the compression stroke to give it a running start into the next one. First thought was dead battery. Jumped it from our van, made no difference. Bypassed battery circuit, connected jumper cables to chassis ground & pos pole on starter, no difference, so concluded starter was bad. Replaced starter, no difference. Had battery tested, & it failed, so replaced it, no difference. I can short across solenoid contacts, no difference. Connect directly to starter from external power source, same thing. If I back the engine up manually to the back side of the compression stroke, it gives it enough of a running start that within 2-3 x of doing this the engine starts & runs fine, so it doesn't appear to be that something has changed about compression resistance. I don't know what else is left that could be faulty.





Mike