...Why the fuck would I need a chain on my lawnmower? AFAIK, push mowers are all direct drive for the blades, and riding lawn tractors use belts.
Carburetor, not 'carborator'. And it's mostly the most polluting engines--lawnmowers, chainsaws, etc.--that are still using carburetors. Every thing else that uses gasoline has switched to fuel injection.
And last, DO NOT LET ANYONE OTHER THAN A PROFESSIONAL CHANGE THE SPRING IN YOUR GARAGE DOOR.