Throttle return spring

[joe912/62]

Just wondering if it matters if the return spring is installed with the short side on bell crank rather than under the #2 intake runner? I noticed mine is backwards.

[mb911]

Um so for what car? 912, 911 with carbs, 911 with MFI, 911 with CiS, 911 with motronic?

[joe912/62]

Sorry 82SC

[Flat6pac]

82 SC, I believe has 2 return springs on the throttle console on top of the motor.
Bruce

[joe912/62]

Yes it does have 2.

[EC900]

The leg of the spring affects the spring tension rate.
The long end will have less pull than the short end (where the spring coils are) being the high tension side.
How it hooks upwards/ downwards could be a problem if the end hook is catching or rubbing on something solid.

I can’t speak of the orientation of your particular set up -
but there are applications where it’s quite obvious which spring leg goes where. The short or coil end would usually be attached at a stationary end of the set up allowing the tension rate to be less at the pivot point.

Can’t hurt if you flip your spring leg ends maybe it will solve the issue.
And I forget, are the engine throttle bell crank lever bushings in good order.?

[joe912/62]

I went for a short drive this morning and upon arriving at my house the idle began to surge. I put the car in neutral and checked if the pedal was stuck and it wasn't. I opened the engine hood and pressed on the accelerator rod and it wouldn't kick down. I had to shut the engine off. When I restarted it was still high around 1800 RPM.

[Kraftwerk]

I have no experience with this, but did you try to put the old spring back on and see if it was still surging? Just curious...

[EC900]

So prior to this morning’s drive, the idle was proper 900-950 rpm?
Then after a full warm up and drive it jumped to 1800 rpm?
Is it still at high idle 1000’s at stop lights in neutral?
Did you drive today with carpet and floor board removed ?

Not to discount any distributor problems in your other Post, is this surging problem sporadic or causing other driving performance issues?

As for sticking linkage high idle… In my experience with the throttle rod sticking, it took some figuring out before I found the bushings had crumbled away. It wasn’t until I removed the front carpeting including the section on the tunnel and floor boards…then go for a drive did I find how the linkage was binding. I couldn’t replicate the binding by hand with or without engine running, strictly a problem that would be under load of foot pressure and shifting.

[joe912/62]

It mostly seems to happen when I slow down to a full stop when I'm in second and wait for the light to change. In all other gears it doesn't occur.

[EC900]

I still think there’s binding going on. Only time I seen another veh do this was a Toyota that the linkage was dirty and dry, hanging up on a kick down rod and high idle vac diaphragm.

Do you have a shift console? Did you take it out?
I ask because it’s a pain to get out easily just to get a real good look at the linkage and bushings inside the tunnel.
Are you test driving without carpeting, center tunnel carpet and floorboards in place? That’s what I had to do as there’s was no way to replicate the binding by hand, had to be with engine under stress and clutch manipulation and even then it was sporadic.