My 1994 250 Yamaha started making a loud clanging noise while cruising today. At first I thought I chipped a piston so I slowed to limp back to port. Traveled 10 miles at a fast idle which kept the noise down. At the dock I discovered the motor was fine as it did not make noise in reverse. Could this be a chipped tooth on only a forward gear? If it was a bearing I don't think it would last 1-1/2 hours or only make noise in forward not reverse. Thanks ahead for any help.