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Thread: Idle

  1. #1
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    Idle

    After synchronizing the carbs (working the linkage at the motor) and adjusting the idle to 850 rpms when warm (previously adjusting mixture with plug checks), took it out for a ride. Came to a stop light and the idle very slowly comes down to 1100 rpms and no further. Is the linkage binding? Carb internals worn? Looking for a solution.

  2. #2
    Yoda poolboy's Avatar
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    Re: Idle

    If they are SU carbs maybe the holes for the throttle shafts need bushings....too much annular space will increase the air coming in and the idle speed along with it.
    DRIVE 'EM IF YOU GOT 'EM

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    Obi Wan M_Pied_Lourd's Avatar
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    Re: Idle

    It's possible the linkage is binding especially around the bellcrank area underneath the front car. Can you bring the idle back down if you hook your toe under the accelerator and pull it up?

    Cheers
    Tush
    81 TR8, SATPL
    73 TR6 CF4874UO
    68 TR250 CD5228LO,
    60 TR3A TS69891LO, 60 TR3A TS64870L, 59 TR3A TS44836LO

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    Re: Idle

    That's what it feels like. Good point. I'll try that.

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    Senior Member jfarris's Avatar
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    Re: Idle

    Frank,
    I usually don't like to comment on something that I haven't tried. I have the same problem with my 56 TR3, won't idle below 1,500, but I can push the linkage under the hood back to an 800 idle. In a thread on BCF, I read that the universals on the linkage at front of the front carb tend to bind a bit and can cause the throttle shafts to leak (what Ken said) or just bind at the bellcrank and not let the throttle plates go back to idle (what Tush said). The recommended fix, that I have not tried, was to get 1/2 turn more compression on the two springs (just in front of each carb body) on the throttle shafts. I have not tried this yet, but looked at the springs and retainers today. I don't think I can see where the spring tabs will be held if you go 1/2 turn tighter. I am only suggesting that you look because it may be a week or two before I can try this remedy myself.
    Good luck!
    Jim Farris
    56 TR3 - Salvador Blue
    73 TR6 - Pimento
    13 Mini Cooper S Bayswater Edition - Blue

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    Yoda CJD's Avatar
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    Re: Idle

    Quote Originally Posted by jfarris View Post
    Frank,
    I usually don't like to comment on something that I haven't tried. I have the same problem with my 56 TR3, won't idle below 1,500, but I can push the linkage under the hood back to an 800 idle. In a thread on BCF, I read that the universals on the linkage at front of the front carb tend to bind a bit and can cause the throttle shafts to leak (what Ken said) or just bind at the bellcrank and not let the throttle plates go back to idle (what Tush said). The recommended fix, that I have not tried, was to get 1/2 turn more compression on the two springs (just in front of each carb body) on the throttle shafts. I have not tried this yet, but looked at the springs and retainers today. I don't think I can see where the spring tabs will be held if you go 1/2 turn tighter. I am only suggesting that you look because it may be a week or two before I can try this remedy myself.
    Good luck!
    I've tried it and it worked on mine. One side of the spring locks into a brass insert tied to the side of the carb. The other is loosened/tightened with a 1/4" nut and bolt. This does, of course, assume there are no issues with the carb (binding or worn shafts) or linkage (belcranks and rods in good condition and geometry). I had new shafts and completely rebuilt linkages, and tightening the end spring brought the idle to rock solid setting every time...no more "blipping" or pulling it up with your toe.

    Here is a pic...obviously a "before" pic, showing the shaft end spring.



    You just loosen the tiny bolt, wind the spring a bit tighter, and re-tighten the bolt.
    John

    1955 TR2

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    Re: Idle

    I thought about that when I was lubing the joints. It seems that the more pressure that you put on the linkage to return, the better it would work. I was a little intimidated to loosen the nut because I didn't know how the spring would uncoil. But I think that I'm going to try it. The revs do return to idle with a little pressure by hand on the linkage.

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    Re: Idle

    I tightened the springs and the motor returned immediately to a nice 800rpm working the linkage by hand at the engine compartment. But when I took it for a ride the idle would not go below 1000rpms at a stop. Since I'm working by myself, I can't see if the accelerator pedal moves when I'm working the linkage at the engine compartment. I'm assuming that it does so I'm still confused why it doesn't return to a proper idle when I'm driving the car.

  9. #9
    Luke Skywalker trrdster2000's Avatar
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    Re: Idle

    Frank, time to start spraying some carb cleaner around the intake manifold and butterfly shafts. If the idle goes up you have found your problem.

    Wayne


    '37 MG TA, '49 Triumph Roadster, '70 TR6, 2000 Jaguar XK8, '78 Spit6

  10. #10
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    Re: Idle

    Just went through this exercise on my 1958 TR3A. I just finished resolving a few weeks earlier. Issue was that when driving the idle would remain high at a stop light. It was suggested that the trottle (sp?) shaft on the right carb could be worn due to the linkage pulling over time on the trottle linkage.

    I had to agree with this assessment and did two things:

    1) Sent the carb body to Apple Hydraulic in New York to have the carb body reamed and a new bushing and throttle shaft installed. I shipped from California on Monday and it arrived back on Friday. Check the website for instructions for shipping. Price was $85 plus shipping.

    2) I also purchased a new throttle shaft linkage from a supplier based in Seattle. It was worn. Not sure if it was needed, but I am very happy with the results. I recall the price was about $100.

    So the good news is that it can be fixed. I am extremely happy with how things turned out for me. Good luck.
    Steve

    TR3A - 1958 - British Racing Green
    TR4 - 1962 CT16758LO - Red, Wire Wheels, and Surrey Top - Owned for 25 years and restored.

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    Re: Idle

    Quote Originally Posted by SteveBones View Post
    Just went through this exercise on my 1958 TR3A. I just finished resolving a few weeks earlier. Issue was that when driving the idle would remain high at a stop light. It was suggested that the trottle (sp?) shaft on the right carb could be worn due to the linkage pulling over time on the trottle linkage.

    I had to agree with this assessment and did two things:

    1) Sent the carb body to Apple Hydraulic in New York to have the carb body reamed and a new bushing and throttle shaft installed. I shipped from California on Monday and it arrived back on Friday. Check the website for instructions for shipping. Price was $85 plus shipping.

    2) I also purchased a new throttle shaft linkage from a supplier based in Seattle. It was worn. Not sure if it was needed, but I am very happy with the results. I recall the price was about $100.

    So the good news is that it can be fixed. I am extremely happy with how things turned out for me. Good luck.
    Some background. I tried taking apart the trottle linkage and lubricate/ grease all connections. This did not help in my case. It was the worn throttle shaft causing the throttle butterfly to stick when returning to idle.
    Steve

    TR3A - 1958 - British Racing Green
    TR4 - 1962 CT16758LO - Red, Wire Wheels, and Surrey Top - Owned for 25 years and restored.

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