Must be from Knott's Berry Farm miniature world
Paper towel is fine to get size
I have one of those at home
Way to thick for a bearing and curve is not enough, yes could be a balancer weight for crank but never pulled apart a Lima engine so can't say, and it would be odd, IMO, to balance a crank that way, usually you drill out a hole to lose weight, or drill a hole and fill it with heavier metal to add weight
To put a weight like that on a rotating mass like a crank shaft would be just asking for trouble, lol, if/when it came loose it would put a hole in oil pan, break a piston, or................?? but nothing good