Throttle servo issue.

[Dieselaw]

Well i installed my new HiTec throttle servo. The model that is nearly an exact swap with the stock servo. Everytging went well. Pulled the old, installed the new, removed the servo horns, set controller to neutral on my throttle adjustment, set controls in "normal", turned in controller, turned on receiver, setting servo to center. Then i installed the horns with linkage ( linkage was same setting as stock). All looked well. I went to start it up. It started , so i adjusted my idle speed with my controller. It seemed to be backwards, the car wanted to take of when i hit the brakes. I read about this so i redid my servo setup with my contols in reverse. Started it back up, and all seemed well. I gave it some throttle and it responded, but when i hit the brakes it TOOK OFF. Wide open until i hit the throttle again, then it would start acting normal ( as best i can tell). Let me know what you you guys think, and sorry for the long write up.

 

[ndoty]

This could be a couple things. First check the return spring to make sure it is closing the throttle once you let off the brakes. If it is not tight it will actually bind in the slide and push the rod to apply throttle. Second you should never adjust idle from the radio trim. This will cause an issue when braking as it closes the throttle to the point it dies.

 

[Dieselaw]

I wouldnt call it a full idle adjustment. My idle was perfect before, but the position of the horns before and after the new servo are slightly different. More of trimming. But i will look into the first part , keep the ideas coming! Thx

 

[ndoty]

I am betting in the spring. When i adjusted some things i didnt push the spring up tight and when i hit the gas it would work. Hit the brakes it would be fine until i let off. It would blip the throttle and keep driving even though my trigger was at neutral.

Just have everything in neutral position and slide the spring back against the stop on the throttle side until it touches. Then slide it slightly more to add a little tension. When applying brake this same spring should compress almost completely. When you let off the brakes this spring keeps the throttle rod from moving.

 

[Dieselaw]

I was just running it a little, and it seems to be doing exactly what you described. Drives normal until i hit the brake. It will stop, but as soon as i let off it wants to take off , just for a second or two. I will give it a better look int the afternoon tomorrow. Im a little confused on the springs and how they work, but i will look tomorrow. Thx!

 

[ndoty]

Your linkage may be on the other side but the direction is the same.

Full Brake should look like this:

Neutral should look like this:

Just in neutral have the spring compressed just a tiny bit.

 

[Dieselaw]

Well you got me tinkering now! I went and looked and i think i found the problem. The throttle arm works normal when using throttle. After using the brake the arm seems to "roll" , which causes it to jam just slighlty until i hit the throttle again. I wonder if i could try another hole on the servo horn to reduce the hang up.

 

[ndoty]

The spring is what keeps the rod from hanging in the slide on the horn. Or are you talking you have a hangup with the rod somewhere else?

 

[ndoty]

Hope this helps.

https://plus.google.com/photos/+NicholasFaustDoty/albums/5511938655089285681/6063200383250333298?pid=6063200383250333298&oid=100071262579387765021

 

[Dieselaw]

After using the brake the actual horn gets stuck sliding down the throttle arm leaving the throttle arm at half throttle. I am going to try and change the hole i use on the servo horn to see if that does the trick. If not a longer spring might be enough to push through the little jam up. But i am open to ideas.....

 

[ndoty]

Yeah it is the exact same issue i had just mine was sticking at 1/4 - 1/8 throttle. Check out the link i posted with a video. It should help show what should be happening. Did you have to switch horns? If so just try to line up a hole at the same distance from center as the old horn.

 

[Dieselaw]

Thanks for the video. I first noticed my spring doesn't reach from the throttle end to servo horn. The only way to get my spring to touch is to adjust the bottom stopper to keep constant pressure on the horn. I am gonna try a different hole on the horn and see what happens. That might stop the binding....