OK I'm reading through the Bob Pastarello's first post regarding gas engines and came across this

7. Remove and toss the "stop screw" on the throttle arm plate, then unhook the little spring that pulls the butterfly closed, unless you want your throttle servo under constant load/tension. DO NOT REMOVE THE SPRING..

I removed the spring because it was binding. Could this be my problem? Not sure why he said not to remove the spring.