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HIF44 high idle

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  • HIF44 high idle

    Hi - I have an issue with my 1330 engine I am trying to sort, and could use some help. I have a fresh 1330 with a hif44 carb. Engine wants to idle at 1600 -1700 rpm, and won't come down anywhere near 1000. Here's what I've checked so far (in addition to hunting and searching the forum and web for clues...): idle screw is out (not touching throttle cam), choke is off (cable is slack), no signs of air leak from carb to intake area, intake to head area, crankcase breather (connected to carb), dizzy vac (either end), spindle ends, choke area. Mixture is close (plugs are chocolately and lifting piston raises rpm slightly then settles at orig speed (although high)). Damper cap is LZX 1511. Dashpot oil is sae30, spring is red. Needle is BCE. Timing is close (10 deg at 1700, vac off). Coil is new, elec dizzy.

    Here's what I'm not sure of that might be contributing: butterfly has poppet valve with spring that seemed soft, carb piston has about 1/8" vertical free play prior to damper being engaged - not sure if that is normal. butterfly valve has some side to side play when opened. Car has slight run on, but if I back off the mixture, the run on lessens. I suspect run on will be corrected with proper idle. It's getting too much air from somewhere...but where? I am missing something...but what?



  • #2
    How did you test for vacuum leaks?

    If you can afford the car, you can afford the manual...


    • #3
      There are two idle speed adjustment mechanisms to check. The one screw that you have backed off the idle cam and the other is the fast idle screw, located at the aft end of the throttle quadrant, kinda where the throttle cable is attached. Have you checked the adjustment there??
      Last edited by Jerry; 06-08-2018, 12:27 PM.


      • #4
        I sprayed carb cleaner at the specific areas to search for air leaks, listening for changes in idle. There was none.

        I'll have to look again for the fast idle, because from my checking so far the only thing I can see that adjusts the fast idle is the screw which contacts the throttle cam. That one is clear of the throttle cam when the choke is out, and has some clearance before it engages the throttle. Is there a different adjustment I need to look for? Thanks!


        • #5
          Without being there to use my pointing finger, the idle adjustment is done using a flat tipped screwdriver on the screw in the recess at the top right side of the carb, as you look into the engine compartment. The fast idle screw is a small hex head bolt, probably uses a 1/4" open/box end wrench, at the lower end of the carb throttle quadrant (lever) where the choke cable attaches to an eccentric (choke lever). Look for the little arrow. That’s where the fast idle is engaged when you pull the choke. See fig. 16.4 on page 4a-19 of the Haynes manual. Check those two adjustments; one at the idle screw and the other at the fast idle screw and cam.

          PM sent.
          Last edited by Jerry; 06-08-2018, 10:25 PM.


          • #6
            Thx Jerry! Got it figured out. It was the poppet valve in the buttery. I soldered it shut and now have steady idle set at 1000 rpm. I could drop it a bit if desired...but now I can tweak things as I continue to break it in. No time for forums now...its driving time!


            • #7
              Glad you got it figured out. Never heard of a poppet valve on the throttle butterfly, particularly something that obstructive. I've always thought that unrestricted airflow into the engine is a good thing...
              OK, who removed their dashpot/piston to check if they have a poppet valve installed on the butterfly? C'mon, be honest!! I did.
              Last edited by Jerry; 06-11-2018, 02:26 PM.