That **** that is safety wired is the governor adjuster. The governor is mounted under the carb, not a throttle body. It has to be be precisely adjusted to work properly. That is why it is wired after it is adjusted at the factory. Those governors can break and cause the motor not to rev up. You could take the carb off and check to see if the throttle plate in the governor is open. If not, then the governor is bad. The exhaust smell and stalling is probably a different problem with the propane regulator.