Motor won't shut off

I have a JD la150. First off the motor won't start unless I unhook one the coils. Doesn't matter which one. They both get spark. Runs fine if I have one of them unhooked but when I do that the mower won't shut off when I turn the keyswitch off. I have to cut the gas supply off to cut it off. I installed two new coils and new plugs. Any help would be appreciated.