rpm stuck on high

[shelby987]

I FINALLY get my truck back on the road, and on my way home from the exhaust shop, this yahooo tries to cut me off, so I floor it ahead of me is open road, but I realize my foot is not on the pedal......but my truck is still keeping speed....even accellerating, step on the clutch, and the tach screams up to 4k before I can let the clutch back out to slow the engine down. I popped the hood and from what I can see with a lighter (yes, gas and lighters....bad.....did the best with what I had at 10pm on the side of the road). Anyway I couldn't see anything obviously wrong (I know very little about carbs)....the carb is recently rebuild (not by me), after pulling on some linkages I thought might be stuck, I jumped in, and the "idle" was down to 2,500 rpm, so I drove home in idle, shifting gears as required......when I get home tonight, can anyone point me in a direction that might get me a little more street friendly again?
p.s.
its a holley 4bbl 'economaster' mounted on top of a 250 l6.

[Huck]

Stomping down may have bent a piece of the linkage either connecting to the carb or on the carb it's self. Carefully (without lighter) disconnect the link between the gas pedal and the carb--at the carb. Does the carb throttle lever move?? The butterfly inside the carb (not the choke plate but the air plate) should be closed---it is partially open? Did you pop off a vacuum line as that can make the engine idle way high too! This should not be a major issue but with holley carbs----anything is possible. let us know what you find~~

[Yukon Jack]

Also, fire it up with the linkage disconnected and see if the idle drops down to where it ought to be.

[bigjimzlll]

motor mount....lift the hood and "power brake" it a little and see if the engine lifts up on the drivers side

[Orange]

Don't have much to contribute, but just be glad you have a manual trans.
I broke a throttle spring one time getting on the interstate. This is when I worked about 30 miles away from home. I felt what it was as soon as it happened too.

I drove to an exit where I knew I could shoot straight across to a gas station, but holding a truck back that is stuck at 70mph isn't that easy. Then I had to kill the engine with it revved that high...puked anti-freeze out the overflow and such. Yucky.

Just a related story.

[shelby987]

Pretty sure the linkage is ok, but I will check, maybe something on my mounthing bracket got a little outta wack......lighter will be left behind.

motor mount? Can you elaborate on how that could cause such a problem?
Also, can you "power brake" a manual transmission? With 4.56's and a stick.....off the clutch at 2,000rpm means movement!

[bigjimzlll]

Heel and tow in third or fourth gear...just enuff to see if the motor mount is broke. When the engine mount is broke it can allow the engine to torque(lift) the driverside of the engine quite a bit. This can put a tension on the linkage. Never had it happen with a truck, but quite a few cars in the past.

[Longhorn Man]

normally the broken motor mount will only hold for a moment...

have you looked at your return spring?

[shelby987]

I couldn't see it last night, but when I originally hooked up my 4bbl carb, I had to fab up a 'backyard' bracket to the return spring, I ended up running the return spring to a bolt on my pb booster......but failed to remove the original, short and large in diameter spring......my quick acceleration threw the spring around, and when the throttle went to close, the spring got stuck between the bracket and the throttle.....pulled the spring and runs fine.....thanks for the advice!

pretty sure I would have seen it last night......I am going to blame it on the dark