Nitro .OS SH 28 engine full throttle run away

[hueyc586]

Hello, I have a question hoping maybe you can shed light. I have Redcat XTR nitro with.28 SH engine. I have excellent power and response but notice when letting off full throttle on straight run, at times the engine rpm would actually speed up almost like run away situation with no throttle. It is very strange as i don't see this happening on my other nitro cars. I can't say that this is consistent each time but after several full throttle action, I've notice this happening. It will eventually coast to stop or idle but not immediately. If I apply break it will stop. Any concerns on symptom? the engine has plenty acceleration and blue smoke throughout the range.

 

[Tunedfrog]

Is there a return spring on the carb?

 

[hueyc586]

Is there a return spring on the carb?

Not that I am aware of. I've taken the carb apart cleaning and did not see any return spring. It is OS 28 SH carb came with Hurricane.

 

[Tunedfrog]

Most carbs if not all have a return spring just for that reason.
It sounds like to me, when you let off the throttle it isn't returning to the idle position, a return spring does just that.

 

[hueyc586]

Most carbs if not all have a return spring just for that reason.
It sounds like to me, when you let off the throttle it isn't returning to the idle position, a return spring does just that.

Gotcha! I've tested the throttle linkage from idle and the gap does respond accordingly. If rule this out, what else to check?

 

[CertifiedMike]

Your throttle linikage is binding. It needs readjust like @Littlemotor pointed out.

 

[olds97_lss]

Your throttle linikage is binding. It needs readjust like @Littlemotor pointed out.

Or your throttle servo is flaking out on you. I've had both issues... sometimes on the same truck!

 

[CertifiedMike]

Or your throttle servo is flaking out on you. I've had both issues... sometimes on the same truck!

Thats fun!!!
We have a pic of this linkage. Its def the place to start.
The motor was loose and it went bad from there.
Motor is retight, now we need to unmess the mess!
This car should be ok with adjustments, hopefully no parts.