have a 2000 42" 18.5 vtwin craftsman riding mower automatic - been working great- went to cut grass today- pulled lever up to engage blades and blades would not turn- about 10 sec later they kicked on- noticed while cutting they would shut off a few times like i disengaged lever then kick back on a sec later- i went threw and cleaned deck- lubed cable & linkage - 50% of the time blades will engage -did notice belt does tighten up like it should - is their a switch going bad or?? whats your thoughts?