Moisture inside the grass crossing terminals. Good find........Update time, I was looking thru the circuit again. Noticed that there was a buildup of dirt/grass on the connector to the key switch that looked like it was crossing multiple terminals. Took connector off switch and blew all off with air compressor and reattached. Mower now starts and seems to be fixed. Seems that the dirt was causing a short that caused the 15 amp fuse to blow. Thanks all!