Help with engine

[Redneckchevy]

Just replaced throttle return spring...Every time i turn truck on its as if im flooring it...Wont kick down....Spring works...Throttle plates are closing....I dont get it
Cant see any cracks or nothing...Secondarys are closing....Idle is set so the engine plates are 100% closed...

[VileZambonie]

did you knock the vacuum hose off of your brake booster?

[Redneckchevy]

nope every thing is on right...Just replaced the spring and she went crazy on me....Every thing looks to be fine...Its crazy...Put my hands over carb..Started Running slower but chugged and stayed at about 4000rpm

[VileZambonie]

Take the air cleaner off and take the spring back off, now with the engine off make sure the throttle is working correctly. Sounds like you have a vacuum leak or your spring is opening the throttle not closing it.

[HAULIN IT]

Redneck, What kind of carb is it? It is running @ about 4000 RPM with the throttle blades closed? Did you remove/change the bracket for the return spring? Possibly sucking air through a open hole?  Will try to help, Lorne 

[Redneckchevy]

Yea every thing is working..spring is closing plates...its a Holley 80457
I dont have any emission stuff...Just 1 vacuum port for my advanced and another for brake booster..every line is new...I dont get it.

[VileZambonie]

You're positive no vacuum lines fell off? plug your brake booster hose. If you look straight down inside the carb (engine off) you can physically see the throttle plate is closed?

[Redneckchevy]

yep its closed..no lines are off..i even took all pressure of the pump acuater and it still revs high...And its a stumbling high...Not a smooth rev...Flaps are closed..No pressure on the fuel acuater...But yet its reving ...WTH im about to junk it...or buy the truck down the road for 2000 with a 454 c30

[Redneckchevy]

Well i give up...i can get a 5.0L 4BBL out of a 85...Any one know if thats a 350 or 305?

[HAULIN IT]

Redneck, A 5.0L is a 305. I know Vile asked, but are you looking down in the carb or looking at the linkage on the side? Something is goofy here, do you have a tach & see it at 4000 or are you just implying "it's really revving"? That is way to high for even a large vacuum leak, there has to be fuel going in with it. Please explain : "You say every line is new" Have you run this engine since you put on the hoses? Did you try pulling off the hose going to the distributor & plugging it? Why did you change the return spring? There are only a few things that could do this (if it is really @ 4000, just the carb, I would guess) Don't give up, this has to be simple. The motor itself is not at fault, it is just reacting. You need air & fuel to increase the RPM's.  Just trying to help ya out, Lorne

[Redneckchevy]

Well i replaced all vacuum lines a week ago..Replaced pcv valve..And valve cover filter...I replaced the throttle spring cause the old one was week I have a Actron digital timing light that has rpm reader...Um yea i did as ville said...I climbed up on the truck and looked down plates open and close..Back plates open and close when i open the secondaries...Every thing was running great...I installed the spring and went to start it and its just revving out of control i give it gas and no difference....But the peddle does open it and the spring does close it...Only other thing i did to the truck is remove the header block off..the thing at the end that will close it in cold weather...I made sure it was free flowing...Im lost...Iv been out there all day searching ...Put my hands over the carb and made it air tight ..best that i could..and it still ran high and rough

[VileZambonie]

Redneck,
Unless the throttle plate is open you have a vacuum leak. The only thing that can make your gas engine rpm increase is more air being let inside the intake. Pull the throttle cable off and return spring off. Manually work the throttle and make sure it closes. Try running it for a second with the throttle manually closed with them off and see what it does. Is the carburetor loose? If all else fails pull the carb off and see if the base gasket is in tact.

[Redneckchevy]

yea i did what you said...The plates are closing im going to take the carb off tomorrow and replace mounting gaskit ...i just dont understand..Every thing was fine till today i think tomorrow ill make a video of it and post it...

[TexasRed]

what line is your PCV valve hooked up at? Did you have a backfire? Maybe your powervalve got fried? But it still sounds like there is a vacuum leak.

[Redneckchevy]

No i just rebuilt carb...It was running fine..Went out to start it then this had to happien....No back fire..pcv is hooked up to front of carb...I cant find the leak...I wounder if a blocked header could do this?
cause i had that thing on there that will close of the header to help warm up the engine fall of the other day..it wasnt hooked up to nothing but the valve might of stuff..blocking the right side header