I have a mower that only has 130 hrs. on it. It is a 2015 model with a Kawasaki engine. It has the manual lever to engage the PTO. Lately the PTO is slow to engage. Sometimes takes 25-30 seconds to start turning the blades. The cable is in great shape. Lever is not bent. What could cause this? PTO just going bad or could it be that I have never changed the deck belt. It doesn't appear to have any cracks and isn't frayed any. I know I should have changed it by now anyway.