'52 Chevy truck act like it's on cruise control

My old truck has started something new and challenging. The engine revs itself and I have to literally put my toe under the pedal and pull it back up or it will accelerate itself. Once I do this the idle comes back to normal but if I take my foot out.....off it goes again. I unhooked the linkage from the gas pedal to the carb and it still does it. Anybody out there that can help me?

 

Sudden big vacuum leak?
Did something fall off the intake manifold?
Choke cam pushing on throttle lever?
Lose a return spring?

 

I am wondering if it is the choke...I have two "pull" ****ons in the cab. One is the "T" which I ***ume is throttle, and the other is "C" which I think is the choke...problem is the "C" ****on is not there and hasn't been since I got the truck. It just started revving recently.

 

SMOG_GUY is probably correct, check the vacuum wiper hose. Cracked? Vacuum wipers?

 

It is vacuum wipers. Thanks for the tip, I will check and let you know what I find. Thanks so much for your help.
OLY20

 

I you lift the accelerator pedal it goes back to normal idle?

Sounds like a broke or loose carburetor return spring.

 

I am going to show my ignorance....that spring you are talking about is IN the carb? Because once I disconnected the gas pedal linkage, it still rev'd up.

 

What motor, what carb?

I had an Edlebrock carb that would do that when hot.....re-tightened the carb mount bolts evenly and problem solved

 

Can be connected to the linkage or the throttle shaft. Not internal.

 

Just for clarification. I've always seen both. One on the throttle shaft and a double spring on the linkage...either separate as mashed shows...or one inside the other. Please don't drive it until you fix the accelerating problem. I had a throttle return spring issue earlier this year. I was working on my buddy's late '60s Cougar. Luckily I was doing the test drive on my 1/4 mile long driveway which goes through 200 acres of alfalfa. I had to hang a big left to scrub off the speed, and ended up doing 360s through the field and almost went in a huge drainage ditch that crosses the driveway! For those wondering, the brakes weren't up to snuff and weren't helping at all. And no...I couldn't have just turned off the ignition...the cylinder was loose and you needed to reach behind the dash to hold it when turning the key. Believe me, I tried...lol. But the car was fishtailing and picking up speed fast! And the drainage ditch was coming up quick...and then the road at the back of the property...and another ditch...and trees! Gave up on the key and just barely slid past the ditch then yanked the steering wheel to the left...with dust and alfalfa flying. The car came almost to a stop, with the rear tires still spinning, but I was finally able to shut'er off. Whoa!

So after hearing all that, you're gonna fix this before driving, right? Do as I say...not as I do. Lol.

 

If your running a Stovebolt check the return spring on the bellcrank

 

That is the one I disconnected and it still rev'd up. I'm thinking it has to do with the carb...but what do I know? That is why I am dependent on anyone who can help. I so appreciate the responses...thanks to all of you who replied.

 

You do not want to disconnect that spring(if your referring to the pic I posted.)

Reconnect it and make sure it's in good working order. If not go the the auto parts store and get a new spring.

Above the question was asked about what engine and carb your running?
That info will help

 

Can you post a pic of the carburetor and the linkage?

 

I will take a picture of the carb and linkage tonight and post tomorrow....again, thank you all for your ideas and help.

-Jerry

 

here is the inside of the truck .....

 

And it still does it when the spring is attached?
If so, then you have a vacuum leak somewhere.
r

 

aside from the windshield wipers...where would I have a leak? I checked the hose from the manifold to the wiper motor...it's attached. Where else should I look?

-Jerry

 

Have some some gas it while you look and check the operation of the return spring.

make sure the rod returns

vacuum leaks can be at the base of the carb, manifold to head gasket or at the vacuum advanced at the distributor.


where the gas pedal rod hooks up is the bellcrank, make sure that the spring brings that back to return.

Have you rebuilt your carb lately?

earlier you stated the choke is missing
in the pics the choke cable is hooked up. the throttle cable it the one that is cut.

 

Thanks and now you know why I am relying on you guys...I am not mechanically inclined but able to do what I'm told. I can draw it before I can fix it. Carb was rebuilt by our ASE auto shop here at the high school. I really want to be able to fix this before I give up and take it to the professionals.

 

I will video the motor running and try to post...
thanks a ton!

-Jerry

 

Take a can of WD40 and spray around the 'joints' of the intake and carb. Basically any area that two surfaces meet and have a gasket. Do this while it's running and you'll find where a leak is if that is what's wrong.
r