Throttle Return Problems
 

Hey Guys,
YS 1.10, when i "rev" it up and then bring it back to idle it will either be to high or too low. its never the same when i bring it back down. i checked it out and i cant see any hang ups.... any words of wisdom?

-n

RE: Throttle Return Problems
 

disconnect the pushrod from the throttle servo double check for binding. If ok start the engine and see if the engine returns to a good idle mechanically.if it consistantly returns to a good idle then it sounds like your servo is weak or bad.

RE: Throttle Return Problems
 

I could be slop in the linkage. Check to see if it is moving as I have found the flex cable to be the worst about this if both ends are not secure.

JEB:D

RE: Throttle Return Problems
 

Check the pushrod for binding.
Check the servo for return to center accuracy.
Both checks are first done with the two disconnected.
Put a reference mark under the servo arm, don't rely on what it looks like without a marker.

Check the throttle movement on the engine while the pushrod is disconnected.

Sometimes the return to idle is a needle setting problem. Too rich idle, or an engine that richens up through the midrange and carries the excess into the idle can cause what you're seeing. Those carbs can come through the midrange fast and you don't have the idle slowdown. Come through slowly and you do. Do a pinch test on the idle no matter what you're finding.

Now check again with everything connected, but the engine shut down. Engine vibration often jiggles sticking stuff past the sticking points. And might do it in the air and not on the ground where the ground sets up different vibration patterns. And vice versa on the ground/air vibration. And vibration can also cause binding. Finding stuff often just takes trying the tests a different way.

If you haven't found it yet, simply swap out the servo.

Let us know what you find.

RE: Throttle Return Problems
 

use a steel push rod .056 size, i myself have never been able to set up a flexable rod
for a throttle and get it to operate right