Servo or OE problem?
 

RC10GT....I can't get the servo to go full range to open and close the carb. My brother has the exact same truck and his opens and closes all the way. What is wrong with mine? If I get it to close the carb almost all the way where it should be, it won't open all the way on the other end of the servo range. When I get it to open all the way, I can't get it to close all the way. Help!

My GT is a bit tight on the servo travel as well.

Are you and your brother using the same brand of radio gear

All I can suggest is extended fiddling with the linkages to get things to full throw, and check that you have enough spring tension to push the carb fully open.

Note that in the GT, the horn won't be at right angles to the servo when the servo's at neutral.

Yeah, we have all the same parts. I am gonna mess with it today and see if the spring change will work. Thanks!

Another thought is to fit a bigger servo horn on the servo, and get rid of the associated one - it'll need a bit of modification to fit the linkages in, but you can use further-out holes to get longer throw.

Also check the balljoint is screwed into the inner hole on the carb.

Got it working! Full range of servo now available. Thanks!!!