I have new Futabe S9372SV servo I put on the T/B of a new Team Durango DNX8 but it’s “twitchy”.

I called Futaba and asked them about it and he said I could move the arm 1 tooth over to relieve it of the spring on the throttle linkage but that would leave my carb open too far instead of have a proper idle.

He also said it is a programmable servo and using a CIU-2 tool, I could program that out of it so the servo’s neutral position would be where I want it pushing on the spring a little, keeping the carb closed, and not twitching anymore.

Reading all the documentation I could find, I don’t see anything about specific programming.

Anybody ever program servos before?
How does that work exactly?

I've programmed servos before - you'll need some kind of link to the servo so you can use a program box or a PC with programming software. Why can't you trim the radio to adjust? Programming servos is for really special situations -like 2 servos on the same control surface. Or how about a threaded clevis in your linkage so you can manually adjust it? Pretty common stuff for RC airplanes.

Bruce

The guy I talked to at Futaba said I could program it to not twitch.

I thought that sounded wrong.

As for the linkage, it's perfect but as the servo holds against the little spring to keep the carb closed, it makes a humming/twitching sound. I've worked on it that setting the spring tension as lite as possible and the humming sound gets quieter but then the carb doesn't stay closed all the way and I would then have to hit the brake to close the carb to idle.

Adjust the spring more so that the carb is closed but the servo gets louder.

I have 19 nitros and I've seen only one other servo do this before.

And I have worked with the trim & sub trim, Throttle response, and something called B.R.A. and no matter what I adjust with any of that, I still get a humming/twitching sound as soon as the servo feels any pressure at all from the spring.

So programming may help if you can adjust deadband. There may be some other parameters available too - you may want to download the software to see what you can change. Not a lot of info on the Futaba site, other than you can buy the USB adapter and download software for free. Adapter appears to be $45 at Tower Hobbies. Unfortunately that makes a premium servo even more pricey.

Bruce

I'm running into the same thing with that servo on my son's EB48.3. I'm using it as his steering servo, with his 4PL radio. When I turn the controller wheel back and forth quickly (like doing a whip off a jump / maneuvering the car in the air to set up for the next turn), the servo seems like it will go back and forth several times at the same speed, then all of a sudden it's like it hit a turbo boost or something.

I tried lowering steering and return speed, expo, even changed the receiver, but nothing worked. I called Futaba, and the guy said "he'd never heard of anything like that happening".

I had to put the HI-TEC 7955TG back in there for him to race.....it's smooth as silk. I'm going to try it in my buggy with my 4PX to see if it's radio / receiver related.

I worked on this some more the other night and I'm not liking it at all.

$150 makes me think I was getting something really good but I'm thinking this just ain't it.

I have one of these in the steering on one of my MBX6Rs and that seems fine but still a little noisy. Don't notice anything wrong with it when I'm driving.

I guess maybe I'll take this Futaba out of my DNX8 and use it in the steering on something else.

Just not seeing it as something I want to trust for a throttle servo.