Tuning/set up..I know nothing

[sbz]

Hi, so I just bout a hpi rs4 rtr drift car, came with everything i needed. i bought it used. ran about 2 tanks of fuel through it, then it ran empty and died. couldnt get it started, so left it overnight and put a new plug in and it started fine today. then it was bogging on acceleration as i was trying to tune it, and wouldnt start. i reset the screws to stock, still nothing. my friend started messing around with the idle pin and throttle trim because it wouldnt fire, then it would fire and die within a few seconds. fooled around with it some more and then it fired, would rev super high and start driving forward really fast without even giving it throttle on the controller. now it wont fire or anything after he messed around with it some more. can anyone help? thanks, i know its a shot in the dark. the hobby shop can't tune it for about 3 weeks so thats out of the question

also, when you go to pull the start cord, it tries to roll forward like its in gear. like spins all the wheels, and i know that isnt normal because it wasn't doing it before

 

[olds97_lss]

Sounds like your clutch springs have broken which causes the clutch to be engaged all the time. It's going to be near impossible to tune it like that as it will always want to die.

Pull the engine and check the shoes.

In the mean time, you can also read these for some good tuning information:
https://www.rcnitrotalk.com/forum/showthread.php?t=60832

More about tuning and explanations of how/why:
http://home.comcast.net/~98gmarquee/pics/misc/ParisRacingEngineTuningTechTips.pdf
http://www.rchobbies.org/cars_eng-tuning.htm
http://www.rc-truckncar-tuning.com/Glow-plug-reading.html

A walk through on clutch installations:
http://www.twf8.ws/new/tech/clutch/clutches-index.html

 

[sbz]

thanks, ill start there. it never used to always be in gear until he started messing around with the throttle trim and idle pin though, if that makes any sense? it was running and starting fine until it died randomly, then it would pull freely to start without trying to move forward, then when he started screwing around with it(literally) it started to jump forward when pulled

 

[Metalhead Matt]

Sounds like a coincidence. The broken clutch spring is probably what made it go screwy in the first place. Then messing with the needles made things worse. Go just shy of factory settings, set the idle back where it goes and fix the clutch spring. Then give it a go. Make sure your ignitor is fully charged.

 

[sbz]

okay. thanks for the help, as i said i know nothing so i appreciate it. I'm going to pull the engine off and try to check it out. thanks.

i just took it apart, the spring doesn't look broken, it keeps the two clutch pads tight against each other, i can pull them apart, like wider by hand which i am assuming engages it? but then they snap back small when i let go so that doesn't seem to be the problem?

 

[olds97_lss]

Nope, so, it's just a bad tune. If your idle is too high, it will cause the clutch to engage. If your tune is too bad to set an idle low enough, then you have to get it better tuned.

Just set it to factory and go probably 1/4 turn lean on both the HSN and LSN (high speed and low speed). With your radio on and the remote at neutral, check down the carb throat and see if you have at least a 1mm opening and not much bigger. When you apply brake on the remote, the throttle in the carb throat shouldn't move. If it does move, then your radio is setup wrong or the linkage is wrong. The carb should be resting gently on the idle screw adjustment when the remote is at neutral.

Once you check those things, prime it and start it.

I'd suggest reading through those docs I gave you so you understand what changing something does and why you do it before you just start making adjustments.

Let us know how it goes.

 

[sbz]

will do. its 12:43 here in ontario, canada so my neighbours might not like me starting it up, ill post up how i make out tomorrow. once again thanks

 

[sbz]

yup, turned out just to be set up very poorly. thanks all