Engine goes right to full throttle/advance

-
DART66GT

DART66GT

62 Lancer GT - B Body 8 3/4
FABO Gold Member
Joined
Aug 1, 2004
Messages
520
Reaction score
48
Location
Connecticut
I have a 66 dart with a 318 four barrel. I started it for the first time yesterday and it ran good. Started it this morning and it went straight to full throttle. Looked in the carb and there was lots of raw gas. I took the bowls apart and checked for sunk floats ,float level, inlet seats everything looked OK. started it again same thing. Even when bowls are empty it revs right up. HELP!!!!!!!

Please.
 
Also tried without vacuum advance hooked up. vacuum can is not stuck. weights seem to move normally.
 
Throttle plates fully closed. Black soot came out exhaust on the last try. It almost seems like a vacuum leak?
 
No the PCV hose is still there. And I,ll take all the help I can get.
 
Carb bowls are empty and it fires right up and revs? WTF?

Another member here had mistakenly attached his fuel line to his pcv inlet on the carb and I believe it was a eddie carb. What carb are you running?
 
Its a holley 650 spreadbore. The lines are hooked up right and ran perfectly yesterday for about an hour total.
 
Wow! You got me stumped on this one. Could there be lots of rust in the carb from the fuel tank? That wouldn't explain the revving but would explain the flooding. Have you retorqued your intake manifold bolts?
 
im with ramcharger. somethings sucking air. plug the carb with shop rags and if it,ll run its sucking air thru the intake gaskets. also is fuel pressure set at around 7 lbs
 
Retorqued intake bolts. Put fuel regulator in line dropped to 5 lbs. and it runs but still revs like crazy As soon as you open the choke plate. If choke plate is all the way open it is a runaway. Am I getting to much fuel somehow. idle screws do nothing. Any input would be greatly appreciated.
 
Well, an engine won't rev up from fuel alone. It must be getting air and fuel from somewhere.

There is a fast idle adjustment on these carbs. When the choke closes it rotates a cam that interferes with the fast idle adjustment screw. Just pulling the choke open won't drop the fast idle, you have to whack the throttle once it gets warm and the choke starts to come off. You can, of course, back the fast idle screw all the way off.
 
If I choke off the air supply it does die. When I open the choke a little (1/8") it runs lopey. Any more than that and it goes to full throttle. I do get some black smoke from the tailpipe. Can I be hurting the engine running it like this while trying to figure this out? I wanted to try another carb but I don't have access to one.
 
Is the fast idle cam and fast idle adjustment screw holding the primaries open? I don't mean all the way open, but is it holding the primaries open enough to where the idle screw has no effect?
 
I still have a problem with the fast idle screw up on the cam or not...Thanks for the help ramcharger.
 
I did my best, Dart66. 68 Sedan is right, a bad power valve will provide excess fuel, but I still don't think it would make it rev out of control.

If you back the idle speed screw all the way out, it still revs out of control, right?

This problem is driving me nuts. I wish you were closer so I could take a look myself.

Is something interfering with the throttle shaft, like the intake manifold or a spacer? Maybe even a vacuum line binding it up?
 
Are the secondarys closing all the way? I had that problem with the same carb, those big bores only need to be open slightly to make it rev pretty high
 
I got good news and I got bad news. Found the problem. one of the primary throttle blades screws were broken it looked like it was closing but must of been hanging up. The heads of the screws were there yesterday but are now gone. took off the carb and can't find them. Is my only option to take off the intake and maybe the heads? I think I know the answer. Do any of you have magic powers?
 
Ouch! Chances are it went right through, hopefully without any damage. Those screws are brass and magnet won't do you any good. Pull the manifold, then the head to be sure it's not rattling around in a cylinder. Of course if went through, it's money spent for nothing but for peace of mind.

That sucks man.
 
Well I pulled the intake and the drivers side head. Didn't find anything. There is a small ding in one of the pistons though. Nothing fell out of the head. Is it worth it to remove the valves to check? Cylinders look great no ridge and some still have the crosshatch.
 
If you already have the head off I'd say check the valve faces/seats. If everthings ok, I'd replace the valve stem seals since you already have the head off. Looks like it went right through. :) Since head/exhaust gaskets come in pairs may as well replace seals on both sides if there's some miles and age on the motor. If the engine is relatively fresh, just put it back together.
 
I once had a ford 2.3 pinto that I dropped the air cleaner wing nut into the carb and down she went. I think it got past the valve because it knocked like a son-of-***** for about an hour straight. I was afraid to turn it off because I didn't think it would start again. It finally got quieter and quieter until it was gone. I thnk it actually relined one of the cylinders:) I ran it another two years with no issues. Even ran smoother......go figure.
 
same thing happend to me, i just went up to the engine and pulled back to linkage, then it worked fine, i guess it just got stuck. But you have alreasy probably tried this. :read2:
 
Thanks for all the replies on this. I pulled the head and found no damage put everything back together and its running. I do have a weird timing issue but at least its finally running. Thanks again.......
 
You must log in or register to reply here.
-

Back
Top