New Carburetor runs a full throttle

Asked by Mar 07, 2017 at 07:12 PM about the 1978 Chevrolet C/K 30

Question type: Maintenance & Repair

Last fall after having to be towed in idecided today to replaced my carb with a
new rebuilt one from Guaranteed  Carburetors/ after installation the new
carburetor the engine want to run at a full throttle without the throttle depressed
all springs and  vac  hoses appear in place any help would be greatly
appreciated thanks

3 Answers


I would double check your work. Something is wrong and I think it is probably not the carburetor but the linkage or the throttle return spring.


If you look inside the carburetor with the engine off the butterflies should be closed.


Check the curb idle speed screw (driver's side of carburetor) and fast idle speed screw (passenger's side of carburetor). Make sure they're not turned in too far. Curb idle, engine fully warmed up, transmission in drive, vacuum advance vacuum hose disconnected and plugged at the distributor, and parking brake set should be 650 RPMs. Or 900 RPMs in neutral if you have a manual transmission. Fast idle, in park or neutral, engine fully warmed up, fast idle cam on highest step, should be 1500 RPMs. HTH. -Jim

Your Answer:

C/K 30

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