Stuck throttle

Discussion in 'Troubleshooting & Diagnosis' started by Max Jarmoluk, Jan 7, 2020.

  1. Max Jarmoluk

    Max Jarmoluk New Member

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    So just put on a new carb (Edelbrock 600) on my 305 (80-85 year) and when I took it for a test drive I tried flooring it from a complete stop in order to see if I could get the engine to stall from the new carb. Once at 60 or I decided to let off but when I did the throttle just stayed down and just kept revving higher. This being my first time in a situation like this thought it would be a good idea to put the car in neutral (it wasn’t), which then led the engine to rev to 5500 or so where just before I killed it I got a very loud bang and flash. I pulled over (with the engine off) and surprisingly didn’t have a puddle of oil under the block. Check the whole car over and seemed to be fine. When I tried to turn the car on it turned over very very slowly. Upon the second try it turned over just fine and sounded fine once it was running. (I already pushed the throttle back to idle position). Driving it home the throttle still stuck, thank god not wide open this time, and I was able to drive at 40 mph without even putting my foot on the gas. Once I got home and turned the car off and took the keys out the engine continued to turn over (very slowly) AND the cylinders kept firing. After about 5 seconds it finally died.

    PLEASE if anyone knows ANYTHING about this can you please let me know below, I’m going to make sure that my throttle is very unsticky before I even turn the car on again.
     
  2. Gary S

    Gary S Administrator Lifetime Gold Member

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    First determine why the carb isn't closing down. Is the carb return spring in place and not binding up anywhere? Once you get the carb opening and closing smoothly, try starting it again. If it doesn't idle down to correct speed, you likely have a problem in the carb. If it idles right, things are likely OK.
    When you got home and shut it off, it was because the carb plates were still partially open. That caused the engine to "diesel". Dieseling is the engine running on slowly without ignition spark. This happens when the engine isn't idled down and gets too much gas to shut down. Under these condtions, the engine "diesels". It runs on because the engine compression ignites the gas from compression only.
     
  3. Max Jarmoluk

    Max Jarmoluk New Member

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    Thankyou so much I was real worried for a bit
     
  4. COPO

    COPO Veteran Member Lifetime Gold Member

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    Make sure your linkage isn’t binding on something in its way of full travel. Work it manually with the engine off and see where it binds up.
     
  5. ULTM8Z

    ULTM8Z Veteran Member

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    Assuming your throttle return spring is working correctly....

    See what's binding. Disconnect the throttle cable and see if the carb linkage is moving freely. Then see if the cable itself is moving freely (including the gas pedal itself). It's either one or the other.
     
  6. jamieg285

    jamieg285 Veteran Member

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    I had a similar issue (but far less scary) on a new edelbrock carb, but it was the choke that was sticking. On close inspection I found the linkages were all dry and binding. I applied small amounts of grease to them and the problem went away.

    That said, I would definitely be looking at the throttle return springs - they should be strong enough to overcome a limited amount of binding in the linkages.
     
  7. Dave Nelson

    Dave Nelson Veteran Member

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    Check to see if the carb linkage is not binding on the air cleaner.
     
    budro6968 likes this.
  8. budro6968

    budro6968 Veteran Member

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    I put my Bottom of the Air cleaner 180 from where it is supposed to go One time. It was one of those open air types. It ran fine until the One Day I mashed it to the floor. WOT in moderate traffic. I cut the ignition and pumped the pedal turned the key on while in 3rd gear still rolling and Same thing. The people in traffic were like what's this A-hole trying to do. You know that look. It finally released and I drove home like a little old lady. The tube for the Rocker vent on the underside interfered with the base circle of the carb linkage. I didn't use the vent so I did not realize my idiot move til that moment. A pooe your pants kind of moment!
     
  9. Vettenick

    Vettenick Vettenick

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    Operate the throttle with the engine off to see if it hangs up. If it doesn't, then sit in the driver's seat to operate the throttle with the pedal. If it now sticks, you may have something binding with the pedal linkage/cable, even the carpet or floor mat. Just be careful not to operate the throttle too much, you might flood the engine.
     

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