I've got a 1997 Penn Yan Rage. When I advance the throttle to start is and let it warm up, I bring it back to neutral and it doesn't always go in gear. The mechanic replaced the lower shift cable that had a "flat" spot wore on it. Everything worked fine until Sunday when it would not go in gear. I shut it off, advanced the throttle back and forth several times, started it up, and it worked fine. Any ideas???