Here's the update from tonight:
I pulled out the plastic string holder and the spring came out like CRAZY. Ok, so I rewound the spring an put a lot of tension on it so it pulls the cord back in with a lot more force. SWEET! So I hook up the pull cord thing to the engine and same thing. If all the screws are tight it won't retract but if you loosen a few screws a little bit then it retracts very quickly. Also, when I pull the cord it definitely feels VERY lumpy like three revolutions instead a nice smooth pull.
Here's the weed machine in question:
