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  1. #1
    Jr. Apprentice
    Join Date
    Aug 2010
    Denver, Co
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    Default My 454 is hard to start (carb)

    1983 1 ton 454 carb, auto, 2wd, dually. After sitting overnight, you have to pump the pedal a whole lot to get it to start. I'm relative sure the carb could stand a rebuild kit, but i'm also wondering if the fuel pump could be alowing fuel to drain back from the carb? Or is it possible the check valve in the carb is allowing the fuel to leak back? After getting it started and warmed up, you can shut it off for an hour or more and it will start right back up. But if you wait too long, it will be hard to start again. Not a vapor lock type of problem, more like there is no gas in the carb to send down to the cyls to burn. Ideas??
    Mike-Denver but moving to Kansas
    1997 GMC 1/2 ton-stock 172,000miles
    1983 1 ton Dually Project 454/auto 2wd

  2. #2
    Jr. Engineer hundojoe's Avatar
    Join Date
    Feb 2010
    Elk River, Minnesota


    Well id start the the carb rebuild. More then likely the problem is the floats for the fuel level in the bowls are shot. thats why id start with the rebuild, then after the rebuild get the motor running and set the fuel level to the proper height, you want fuel to just start to trickle out the sight hole, then if you still have hard start problems then go after fuel pump. Just the way id go about it. Good luck.
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  3. #3
    Sr. Apprentice 38racn's Avatar
    Join Date
    Oct 2009
    Brighton, Illinois


    What carburetor do you have? Is it a quadrajet? Do you have an electric choke? What you're describing sounds like a problem with the choke assembly. When your motor is cold the choke should be partially to fully closed, (depending on ambient temperature). You're having to pump the throttle because the choke is allowing too much air in. Unless you have a lot of practice with quadrajets, their a real pain in the ass. Don't try to save by buying the cheaper rebuild kit. A good quality kit is more expensive but should have step by step instructions. I've never tackled a quadrajet without these instructions.
    Of course another option is a Holley. Much easier (and faster) rebuild.

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    1982 Toyota 4W/D Powered by GMPP 350 Crate with MSD ignition, Holley carb, Pro Comp electric fuel pump, Be Cool aluminum radiator; TH350 transmission w/ B&M Quicksilver; Marlin Crawler transfer case w/ Front Range Twinstick; telescopic driveshafts; auto lockers; 9" Skyjacker suspension lift w/ Bilstein shocks all sitting on 37" Super Swampers.

  4. #4


    Quadra-jets have always been bad from the factory over time by leaking fuel out where the factory pressed in plugs at the underside of the fuel bowl. Requires a rebuild, drill/pry (depending on carb) out old plugs epoxy in new ones. Unless it's bothering you that much it will stay the same forever. My '79 Quadra-jetted 454 was the same way. I didn't drive it that much so I just lived with it. Has nothing to do with the 454, all q-Jet.

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