52 panhead missing when accelerating

Discussion in 'Engine, Fuel and Exhaust' started by Keith O, Aug 31, 2019.

  1. Keith O

    Keith O Member

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    I have a 52 panhead that I just bought. It is stock motor with S&S super e card and auto advance distributor with drag pipes . To get it started I have to give it 4 twists of throttle no enrichment. Starts 1or 2 kicks. I let it warm up and when I roll the throttle I fine till I get around 3,000 rpms then it starts to die and missing badly. I took it around the block and could shift through 1st & 2nd with a light throttle and if I try to go any faster it dies and starts missing and when it’s hot really hard to start. I tried new plugs ac45 gap at 30. Pulled plugs they have like a black soot on them (not wet). Carb has .0295 and 74 main. Checked coil primary ohms 41 and secondary 19,000. The float was a little low but worked freely. I replaced intake manifold o rings and put 3M 88 tape around and reclamped. Put new insulator block between carb and manifold. New gas and cleaned shut off valve. Anybody have any idea what it could be?
    Thanks
     
  2. Jeff Klarich

    Jeff Klarich Experienced Member Contributor

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    Black soot not good, have you gone through the carb? might be time for a rebuild.
     
  3. Keith O

    Keith O Member

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    I’ll try a rebuild. Thanks
     
  4. Joyflyin

    Joyflyin Experienced Member Staff Member Moderator

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    Welcome aboard, glad to have you here!
     
  5. Keith O

    Keith O Member

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    Thanks
     
  6. flusher

    flusher Active Member

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    Welcome
     
  7. Keith O

    Keith O Member

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    I rebuilt carb and put a 68 in main jet and 28 in intermediate jet. Also put bolts with washers welded on about 1 1/2 into drag pipes. Starts and idles fine. But when you try to rev it it’s back fires through carb. Looks like mist of gas is coming out of throttle body when it backfires. I also have air cleaner off and accelerator off.
    Any ideas?
    Thanks

    It’s a mist of gas coming out of throttle body not most. Sorry!!!
     
    Last edited by a moderator: Sep 10, 2019
  8. Jeff Klarich

    Jeff Klarich Experienced Member Contributor

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    My experience with coughing back through the carb was to much fuel, not enough fuel or timing.
    When it popes back after you blipped the throttle did you notice any blue smoke from the exhaust? That would indicate to me to much fuel.
    Inspect the plugs, how do they look? sooty dirty, to much fuel, to white not enough fuel. JMHO.

    You may want to make a post in the Fuel and carburetor section here on the forum, not everyone looks at the new member introductions.
     
    Last edited: Sep 9, 2019
  9. STEVE07

    STEVE07 Well-Known Member Staff Member Super Moderators

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    My guess would be timing. I am going to move your thread so more can see it.
     
    Jeff Klarich likes this.
  10. Keith O

    Keith O Member

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    Thanks I’ll try the timing when I put it back together. Putting new oil pump in.