On my hyper 8 pro kit with hi-tec servos and reciever, and go 21 7port engine. Recently when i am using the buggy if i hold the throttle down for a few sec if i let go the buggy automaticly goes by itself then I have to blip the throttle to get control of it again.???? does anyone know what might be the problem, its like the servo arm gets pushed back so it accelarates???

On Friday i got a Duratrax Raze and i put ofna servos in it and yesterday the same thing happened to me. I would go to full throttle and it would stay there for a few seconds. I put the stock Duratrax servos back in and i havent tried it yet. I am scared for it to stay at wide open for to long because it is a new engine and i would hate to blow it up.


My rigs: Warhead Evo, Nitro Evader ST, Evader ST and a Raze

Wow, this is a tough one to explain, someone else may do a better job, but here goes...

First set the trim on the controller so that it is braking all the time, just a bit. You do this so that you know that the throttle is as closed as it can be. Start the engine. Does it die? Turn the idle screw in 1/4 turn. Try again. Dies again? Turn the idle screw in another 1/4 turn. Do this until it idles happily on the box. Now undo the grub screws that set the end points on the throttle linkage, so the 'stop' is free. Bring trim back up to neutral, and set the 'stop' right at the servo arm, screw in the grub screw nice and tight. Now check the braking, and adjust as necesary. After a good full speed run, the engine will 'high-idle', this is normal and after 3 seconds or so, will return to normal idle.

Hope that helps...

EDIT: I was also thinking, perhaps the return spring on the carb isn't as strong as it should be. Do you have another 'stopper' on the carb side of the servo horn, with a spring (from a ballpoint pen, pushing on another stopper? Basically so that the spring from the ballpoint pen provides a small amount of extra pressure to close the carb fully so that the only opening is that set by the idle screw? This is a useful tip, I may be able to get a photo of mine for you if you wish...

What Tx?

Im pritty sure I have found the problem i think the throttle servo arm has threaded SLIGHTLY so when full throttle is on it skipw some groives then catches ont the throttle angle i am currently trying to find another arm to fit on.

Ditch the platic servo arms and get aluminum........ Will last a lot longer with out stripping........

Kool where in the uk can I get HI-TEC aluminium ones thx

Check my edit in my previous post...about a throttle return spring...

There is a couple aluminum arms on this page. Just search the internet for "HiTec aluminum servo arms" there in the UK and buy them off line.........

[link=http://www2.towerhobbies.com/cgi-bin/wti0091p?&C=MGA&V=HRC]Servo Arms[/link]

Just use the correct servo arm that is included with your kit. You do know that there are different tooth counts on the servos and horns, mate the wrong ones and you get your problem. Also ditch the Hitec servos, they themselves cause this as the ynever center to the same place twice, so that makes it hard to set up your ride too.

Yea i do know that well im pritty new to off road nitro buggy so they are the better of the hi-tec range but once i get a few mile lol of rc i might then when i need to get a new engine get some better servos.

Hey guy i have changed the throttle arm, and it still does the same thing, what happens is when its accelar it pushes the rod right out then when i brake it comes back in but then its like the spring isnt strong enough to push it back to the origional place to idle again any one got any suggestions???