I just got my 3.2 back from Brison and it now has a returnspring that keeps the throttle closed.
Leave it or cut it off.

Thanks

I always cut mine off. It creates resistance on the servo that will drain the battery. Many will say removing it causes undue wear on the butterfly, but I haven't noticed this.

Dr.1

Hi,
Don't cut, just unhook it from the throttle arm. The spring on thr shaft keeps the throttle plate from vibrating. If you want to run it on the bench without a servo, just hook it up again to keep the throttle closed.

Cheers, Dave

I agree with davewallace, you need the spring tension along the shaft but do not want the torque fighting the servo.

Every gasser carb ever made is designed with something to keep the disc in the middle...
The spring is to close the throttle on the chainsaws that most of them were made for...
If you take the spring completely out the disc will vibrate back and forth, cousing wear in 4 places where the disc meets the shaft at the ends, and the carb body itself on both ends of the shaft..When this happens the throttle can be completely closed and still not shut the engine off....There are a few Walbros with a slotted piece on the end of the throttle shaft, you could take the spring off these and the disc will still be in the center...The old WTA6 on G38s is one of these.....

The drain on the battery is next to nothing. Just take out your multimeter make a splice and test it. I leave the springs on just in case the throttle linkage fails.
Now before everyone flames me, I do use a secondary method to shut down my larger gassers. My smaller gassers I do not, so I use it as insurance.

Most of us just cut the tip of the spring off so that the spring is no longer pressing against the arm. By leaving the rest of the spring in place, you reduce wear on the assembly.

3dbob

RTK is correct. The resistance on the spring is NOTHING and will not make a difference in servo current draw. Have you ever moved the throttle with your hand with the spring ??? There is so little force there its just NOT A FACTOR. Leave it on, that way if your linkage comes off, the throttle will go to idle. Not to mention the vibration issue, its a good thing to have a LITTLE resistance against the linkage exactly like that spring provides....

Thanks for all the input.
I already cut it off. If it wears out before I am done with it I guess I will buy a new carb.
Live and learn the hard way as usuall

It ain't gonna wear that much, Eric. Fly it and don't worry about it.

Dr.1

Maybe I should post a picture of a worn throttle disc and the carb body it was in..It WILL happen..A new WT76 is about $40...

I don't remove or cut the springs on any of my engines for the simple reasons as RCign1 said to keep tension on the throttle plste and also if the throttle lingage should come off the spring will allow the throttle to go to idle. Wait till you have a lingage come off and the throttle plate does whatever it wants till you run out of fuel.

I have a few walbros that seem ok to leave as-is, but one of the tillotsons I have has a return spring that would make most servos beg for mercy, so I guess you have to look at each case individually

I think I will make a spacer or put another spring in.

a short piece of tygon works well if you lost the spring[sm=wink.gif]