Carburator problem

[Ruud W]

Who can tell me what's going on?
Lately, my accelerator pedal suddenly goes down, causing the car to suddenly accelerate. This happens as I try to drive away calmly. Usually when the engine is at operating temperature. I've already cleaned the carburetor and replaced everything. I also disconnected everything that is connected to the gearbox. He continues to do this. It is a 1965 Buick Special with a 300 cid engine and a 2 barrel Rochester carburetor. Coupled to a ST300 gearbox.

 

[tom telesco]

Throttle return spring

 

[Ruud W]

Throttle return spring

Hello Tom, thank you but i have changed the spring and attached second one to it. But no result.

 

[Bob]

I am not finding a picture showing the correct installation of the spring, can you upload a picture of how you have it?

 

[Ruud W]

Hello Bob, the throttle return spring is mounted like the service manual says. See attached picture. I have put on an extra spring for to be sure. See 2th picture.

 

[tom telesco]

Rudd W,

Has the carb. been rebuilt recently???
The spring on the firewall I believe is in the wrong spot. Should be a hole in the arm behind the Orange wire. This will provide more leverage to the arm.
Same with the carb. spring. Try putting the location on the upper part of the throttle arm pulling forward. Again more leverage.
Other than these two things the only others I can think of are the throttle lades have somehow loosened & are binding.

Tom T.

 

[RJHooper98]

A broken engine mount was a common problem. Open the hood and accelerate against the brake, see if the engine flops. Most were campaigned, but some were missed.

 

[Ruud W]

Rudd W,

Has the carb. been rebuilt recently???
The spring on the firewall I believe is in the wrong spot. Should be a hole in the arm behind the Orange wire. This will provide more leverage to the arm.
Same with the carb. spring. Try putting the location on the upper part of the throttle arm pulling forward. Again more leverage.
Other than these two things the only others I can think of are the throttle lades have somehow loosened & are binding.

Tom T.

Hello Tom,
Yes the carburator is rebuilt. Everything is new inside. The spring is attached as the service manual says. See picture. But i”ll try to put the springs the way you describes. Thank you for your input.

 

[Ruud W]

A broken engine mount was a common problem. Open the hood and accelerate against the brake, see if the engine flops. Most were campaigned, but some were missed.

Hello RJ,

It’s not the engine mount. Those are also new. But i checked, and they are okay. Thank you

 

[bob k. mando]

you can also add a return spring to the pedal, but it sounds like you've got something going on. check to make sure it's not binding on something.

race cars always have 2 springs of different diameters, one nested inside the other.

 

[Ruud W]

you can also add a return spring to the pedal, but it sounds like you've got something going on. check to make sure it's not binding on something.

race cars always have 2 springs of different diameters, one nested inside the other.

Hello Bob, thank you.
I followed your advice and mounted a second spring. Put this one in the other one as you describe, and it works, problem solved.

 

[bob k. mando]

that's still a kludge.
.
in a race car, EITHER spring should be strong enough to pull the pedal back on it's own. this way you have a safety factory over a single spring setup as springs can break or fall off or get hung up themselves. and the last thing you want to do is get to the end of the straight and try to turn into the corner and find out that the the throttle isn't going to back off.
.
so, you ought to replace the old spring with a new one as well.