Small Engines (Lawn Mowers, etc.): mower turns but wont start, safety switches, brake switch

Question
i have a craftsman riding mower. model # 917271011 serial # 021298B002807 family # SKH426U1G2RB MODEL # CV15S MOTOR SERIAL # 2721812794 15.5 H/P KOHLER OHV. I REPLACED THE MAGNETO SET IT TI THE PROPER GAP,REPLACED THE SPARK PLUG SET IT TO THE PROPER GAP,CHANGED THE OIL,FILTER,CLEANED THE CARB.AND CHECKED THE GAS CAP AS WELL. NOT SURE WERE ALL THE SAFETY SWITCHES ARE COULD BE THE TROUBLE. THE OTHER QUESTION I HAVE IF I UN-HOOK THE KILL SWITCH ON THE MAGNETO AND SPRAY WITH A LITTLE STARTING FLUID IT WILL RUN FOR A FEW THEN STOP WHEN YOU HOOK IT BACK UP AND SPRAY STARTING FLUID IT WON'T START. STUMPED ON THIS END ANY HELP WOULD BE A GREAT HELP.

Answer
Check the safety switch on the brake, on the seat and on the pto lever. I don't know whether they work open or closed but if you test them and they are either open in both positions or closed in both positions, then it's a bad switch.

The brake switch is probably on the pedal, either under the footrest or just inside the frame.  The seat switch will be under the seat and the pto switch will be somewhere in the linkage, probably near the control or just inside the frame.  Let me know if you have any trouble.  Thanks, PK.