i put a 24hp briggs replacement motor onto my 52'' scag about a year ago(electric start) and the other day after have 3 days of heavy rean the mower started loosing half its power and would sputter. i messed with the wires by shaking them and it started working fine. i tried it on the next property and it sputtered again. while it was sputtering i messed with the coil wires and ignition wires and it dies. now im not getting any power on the black coil wire at the switch or anywhere else in the line. the other wires to the starter, motorm etc are all getting power. Any ideas on what to try?