My 20 year old Yamaha 50 hp outboard will not start. This just is starting to happen, the battery is fully charged, when i turn the ignition, it wanted to crank, but it was cold, so i turned the ignition off, then i tried again and all i hear this time is a spinning noise, it will not engage the flywheel, at least that's my opinion. Being an older engine, if anyone could help, that would be helpful, this is my first time on a blog, so i hope i am in the right place...Thanks for any advice