Need help with a Bearcat 454
There should also be either a sticker located on the frame inside one of the rear wheel wells OR a serial Number stamped directly onto the frame in one of the rear wheel wells.
Using this number you should be able to call a dealer and they can decode it for you to find out the year. Off the top of my head I don't know which part of it would indicate the year.
Sounds like the machine is either leaning itself out or running rich and flooding out. I would start by checking the caborator, making sure all its parts/passages were clean. Check the needle valve and its seat as they can corrode. I would also check that your choke is functioning properly and not stuck.
Hope that helps