Carb Return Spring [Archive]

hdcruzer

09-29-2009, 08:50 PM

Do you guys remove or not even use the carb return spring. The reason I ask is the local track owner reccomended removing mine becuase it can cut into the carb boot and cause air leaks. What do you guys think?

Neobart

09-30-2009, 04:55 AM

A tear in the carb boot will cause you tuning nightmares. I use a 700x25c bicycle inner tube to make rubber bands to pull the carb shut. You get a whole heap of them for next to nothing.

Kicker

09-30-2009, 05:02 AM

I had some trouble with the spring. on a few occations the spring was seperating the fuel inlet from the carb body, 2nd it put the carb slide in a bind a few times causing the carb to stay wide open. I will never use a spring again how ever i do use a rubber band now with no issues.

maint_guy69

09-30-2009, 05:16 AM

mine is hooked to throttle servo arm

depending on servo works just fine

NuthinFancy91

09-30-2009, 05:23 AM

mine is hooked to throttle servo arm

depending on servo works just fine

Only the 2.0's come with those already on. If you have the kit or first gen. rtr. You'll have to install your own.

Errorhead

09-30-2009, 12:39 PM

I've used an O-ring for this. You just have to search alittle for one the right size.

kjthebirdman

09-30-2009, 01:24 PM

My RTR 2.0 came with the return spring as well, but one of the "pro's" at the local track here in Temecula, CA told me to take it off after I blew my stock throttle server. I've been fine without it.

maint_guy69

10-02-2009, 05:52 AM

done it with a fail safe also

but not good if lose battery power

only signal

dnebout

10-03-2009, 09:22 PM

The owner of my track told me to take it off as well. he said it would wear a hole in the boot. I think he was right!!! The only problem now is if I lose a receiver battery waht happens? Will the throttle stay wide open and launch the car like a cruise missile?

maint_guy69

10-05-2009, 04:21 AM

if the receiver battery goes dead or gets disconneted
the spring pulls throttle closed
so goes back to idle
and don't have a run away

Kicker

10-05-2009, 04:41 AM

Having some kind of throttle return is a must. I have seen so many trucks take off cause there rx battery pack died or came unpluged and motors poping cause of this.

Whether its the spring (which i dont like) or some kind of rubber band systems, you must have this or you will have a vary expensive day at the track.

madweazl

10-05-2009, 06:02 AM

dnebout

10-05-2009, 08:41 AM

I'm going to have to figure something out. I'm using a High Torque Digital Hitech servo and I don't think the Throttle return Spring will have the power to bring it back to the neutral position. I'll open the throttle and disconnect the reciever and let you know.

Kicker,
If it doesn't pull the throttle back to neutral, you always have the failsafe to stop the car but as you mentioned above it may blow your motor if you don't get to it in time.

I'll have to figure something out!!!

Kicker

10-05-2009, 12:10 PM

True there is the fail safe if you still have a battery to help it work :) Must have power for the servo to work :D

dnebout

10-05-2009, 01:48 PM

If your servo fails the spring wont be strong enough to pull it back anyways. That spring is there in case the throttle linkage fails. I'm not running anything right now (ran my last car like that as well), hopefully I dont run into any issues.

Just checked it out. Hooked the throttle return spring back up, turned the transmitter and receiver on, pulled the throttle wide open and disconnected the receiver battery. The throttle closed! The only problem that remains is this spring rubbing against the carb boot. I'll try to engineer something and let you all know what will work.

dnebout

10-06-2009, 09:44 AM

That's a good idea. It would have to be a larger ID tubing to fit the spring inside. It might bind even with the larger tubing, but it is a grewat idea. I'll test it when I have some time.

I was thinking:
The spring is curently attached to the carb throat and the other side is attached to the HSN. What if I attached one side of the spring to the servo arm and the other side to one of the motor mount screws. The angle would be a little drastic but maybe I can make a post that sticks up off the motor mount screw and attach the other end of the spring to the post.

RJNicholson

10-06-2009, 11:16 AM

dnebout

10-06-2009, 12:44 PM

You won't ever have an issue with a digital servo closing with a return spring or ouchless hair band that people use.

Digital servos solved the issue that analog had of not being able to close easily when they lose power.

You should be able to move that hitech around just by flicking your finger.

I highly recommend you keep your throttle return spring or band. I have never tore a carb boot using a spring, and if you do replacing a $6 boot is better then replacing your engine.

I hear you. Now that you put it that way, there is no way the spring could wear a hole in the boot before the motor went out anyway. How many gallons have you run with the spring against the boot? Has it ever bound up on you?

RJNicholson

10-06-2009, 02:03 PM

I have about 15 gallons total on my 2.0 buggy. All on 3 different engines.

6 gallon VZB w/ carb spring. No binds or torn boots.
2 gallon Speed w/ carb spring. Same as above.
7 gallon Picco P7R Evo 2 (RIP) w/ carb spring. Same as above.

Never a bind or a torn boot from my carb spring. I will post pics of how I have mine set tonight after I get back from club racing, and it does rub my boot.

I have torn carb boots, but it was from my BCE Race Chassis flexing the rear upward pushing the engine and carb into the Center Diff mount. I fixed that issue with a ALU rear chassis brace, and haven't had another torn carb boot.

dnebout

10-06-2009, 02:25 PM

yeah, I think I may be overthinking this a bit!

30percent

10-07-2009, 07:02 AM

Seems to be some confusion on this one... A throttle return spring or band is required at ROAR races, they will check. Don't rely on your failsafe alone, that is only for signal loss, NOT Power Loss or Linkage popping off. stripping etc etc.

Using a spring alone can on some situations be very bad. It will pull the carb to one side and force an akward torq on the carb shaft. Eventally it can stick wide open return spring or not.. The best way is a rubber band. They are cheap and it evenly pulls on the carb...

Here is a pick of my dirty motor before cleaning and a Return Band from XRAY...

http://i128.photobucket.com/albums/p176/OGlonniesexton/ThrottleReturn-005.jpg

Be sure the Zip tie on the boot is NOT pinching the boot where it clips. Using a tie here will help keep your motor, buggy and rear brakes clean from oil.