If you use a arm on the throttle that is at least one inch long the servo will pull the throttle open easy. A lot of guys worry about the load would be too much on the servo....well it is not. The max load would be at full throrrle only on the arm....and you are not going to be at full throttle much with all the power on hand! That spring prevents viabration from wearing the plate to bore fit. Also if the linkage came loose...the spring will bring the throttle back to closed or if you use a stop...it would run at that speed. I used a nose steering arm that slips right on throttle shaft. Capt,n...over & out!