Moped Army

I have a 1981 colt 4 that i am trying to get to work.I cleaned the carb cleaned the points it runs but not right my question is what is the thing under the spark plug looks like a jerry brake thing .when i grip the handle it bogs the engine down
like a jerry brake what is this for what is this .going to time it next try it and reset the gap on the points well 15 miles an hr is better then dead in the shed.

tks sam