I think this must be a common problem with four-strokes. I ran into this installing an os 120 on a goldberg ultimate bipe. Dubro makes a little pivot arm device that may solve the problem. On the ultimate, I sent the pushrod out past the throttle linkage to a 180 degree turn, then back to connect. It works fine. If you search around, you might find some photographs or drawings that might help you visualize the solution.