66 hours. After cutting grass for an hour and turning off tractor, it will not start backup. Sitting in seat, gear selector in neutral, pto off, turn key, dash lights up, beep heard, turn key to engage starter, all lights go off, nothing. Keep trying after moving gear selector, again nothing. All lights go off. It does this continually till finally it engages and Tractor cranks up. Maybe 10 attempts. Any ideas please?