dcash88

Hello I have been having trouble with this since I bought it. As soon as the truck starts it takes off. I have read as much as I can find and tried many things to no avail. I have tried tuning the idle screw but I can set it so low that it will stall or won't start but even 1/8 of a turn above that and the car is moving at start up. I have aligned the servo and linkage. I replaced the clutch shoes and spring, at this time I found out the spring was broken and thought I solved my problem but no it still engages right away and drives off.

I believe I have ruled out linkage and tuning, please correct me if I'm wrong. I think the problem is in the clutch as it seems like it will never disengage. What is the next thing to look at or how can I diagnose further? Any help would be greatly appreciated. Thank you!

zackS30

So u have both HSN and LSN tuned? Maybe the spring broke again?
Have u tried setting them back to factory? 2,5 turns out from closed for HSN and flush with the carb on LSN.
U need a 1mm gap in the opening for idle.
Also make sure ur trims r set right.

dcash88

Yes HSN and lSN are tuned. I have tried going back to factory and tuning from there with no results. I adjusted the gap to 1mm then set the linkage and servo horn to be at neutral right there. I will check the spring again, what would make it break so quickly? I've read about clutch bearing going bad could that cause this?

dcash88

I don't fully understand how the clutch works, maybe with a better understanding I could diagnose easier. What exactly causes the clutch to engage and disengage?

dcash88

Nice call on the spring i checked it out and it was broke again. I had a traxxas 4146x spring laying around So I put that in and it seems tighter, I'll see if that lasts longer. Why would it break a spring almost instantly?

zackS30

Crappy spring, idk. In my tornado s30 I never broke a spring I never even changed the clutch.
The way the clutch works is while the flywheel is spinning at idle the spring is strong enough to keep the clutch from spreading out and engaging, so centrifugal force makes it engage and disengage. I had heard of people getting a strong spring to sort of time when the clutch engages if u have a tighter spring it will make it engage at a higher rpm making it have harder launches at a stand. Just like in a 1:1 if I left the clutch out at 1500rpm in my Mazda it takes off gently but if I let the clutch out at 4k rpm then it spins the tires and takes off hard.
Trying a better spring could be beneficial, also depending on where the spring broke u could rebend the end of it to hook back on the points where it goes in the clutch and it would make the spring tighter making it launch at higher rpm

dcash88

With the 4146x spring and hpi 17t clutch bell it seems to be working properly. The car no longer takes off when starting it but after a full speed pass It will not come to a stop again. It seems like the carb is readjusting after wot from too much slop. I can see the carb rock back and forth when the servo moves. I have checked to make sure the bolt is tight. Should the carb move at all? Any thoughts or solutions?

zackS30

I'm pretty sure the carb isn't supposed to move. Something is lose.

dcash88

The carb bolt was as tight as i could get with a driver so I tightened further with a socket wrench. It seems more stable now as it doesn't move at all with throttle but moves slightly with reverse. Will be able to test it later.

Finally getting everything sorted. I got it on Craigslist for 100, it looked brand new but needed to be tuned and had the start and take off problem. It seems like it will be worth the trouble.

zackS30

They r pretty cool.
Hope u get it sorted out soon.