Very fast idle speed

Discussion in 'Mech Tech' started by mrt0mmy, Mar 20, 2017.

  1. Hi, I've just had the original carb on my 1972 t2 Devon (ruby) reconditioned as it was completely warn.

    However the it seems to be idling extremely fast. I'm assuming that although a new carb needs bedding in it won't just be that.

    I was going to check the return on the throttle cable, but other then that I'm assuming it's adjust the fast idle screw.

    Can anyone offer any advice?


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  2. Adjust the big idle screw on the side of the carb. Have you adjusted the throttle stop screw and idle mixture?
  3. I haven't done anything yet. Reading up on it and people say adjusting be idle can mess up the accelerating mix so thought I'd ask.

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  4. davidoft

    davidoft Sponsor

  5. Both from cold and when up to temp, it does slow a bit when up to temp but still sounds like the acceletator is been pressed

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  6. You need to set the throttle stop, then the mixture and idle screws to the initial positions. Then fire it up and tweak the mixture and idle. If the carb's been taken to pieces, unlikely the current settings are correct.
  7. Dubs

    Dubs Sponsor

    Sounds like you may have pulled the cable too tight. Make sure the choke is off and the throttle is fully closed before tightening the cable clamp.
  8. I'll check that first. Thanks.

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  9. Thanks I'll work through this. Just need those brighter nights

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  10. Before you mess with screws, make sure there's a return spring on the throttle arm that is pulling the the arm closed on the carb? If the new mechanic has pulled the accelerator cable taught, and tightened to the throttle arm, it might not be returning back to it's normal stop position, or the spring might be too weak.

    If you're certain it's ok and returning back to the stop point, then consider setting the throttle stop screw on the back of the throttle arm.
  11. Having never driven a camper before, or anything older then a 90's car I've no experience, is it usual for the accelerate pedal to have a large section of travel before it affects the engine speed? There is no resistance initially on the pedal at all.

    I wonder if this could be do with how the accelerator cable is tightened.

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  12. That certainly sounds like something is wrong, although you tend to spend a lot of time at full or nearly full throttle in a standard 1600 engined bus to get it to move at any speed, the slightest touch on the throttle should increase the revs when in neutral.
    Follow all the advice above and get some pics if it still doesn't seem right.
  13. Baysearcher

    Baysearcher [secret moderator]

    snotty likes this.
  14. Thanks I'll try it at weekend, I don't wanna wake the neighbourhood up running her at night.

    What's techenders? Where can I find more information?

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  15. Baysearcher

    Baysearcher [secret moderator]

  16. Sounds like a useful weekend

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  17. This is what you need to run through, as your carb's unlikely to be set up already. Straightforward enough if you take your time. Do final adjustments with the engine/carb warmed up.

    To set the cable, make sure the carb quadrant is on the bottom (choke off position), loosen the barrel nut and yank the cable with pliers so the pedal comes right off the floor. Then tighten the nut.
  18. davidoft

    davidoft Sponsor

    The throttle stop should be set, you shouldn't need to touch it, if you think it's not set correctly start from
    Scratch. To be sure the accelerator cable isn't interfering disconnect it. set the throttle stop first then the idle and fuel mixture
    snotty likes this.
  19. Assume nothing!
    Valveandy, 77 Westy and davidoft like this.
  20. So I finally got around to setting up the engine.
    I adjusted the screw on the throttle lever, it was fully in! She's now ticking over nicely but she's doesn't seem as smooth now so I'm going to go through the rest of the set up! Just need more time!

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