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carburetor

Discussion in '40- & 55-Series Tech' started by johnny, Mar 19, 2003.

  1. johnny

    johnny

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    alright here we go.

    i had a holley (2f) but put on a webber 32/36. i didnt like the webber cuz it ran rich and there was a noticable decrease in power. i messed w/ the timing to see if i could get it to run clean but decided to scap it and put the holley back on.

    once on it ran like crap. i can get it to stop back firing. normally this stuff is very simple for me but i cant seem to figure it this time.

    as soon as i crank over the engine if backfires, making it very hard to start, as its starting it winds down like its running out of electricity then it just pops. once runningl, lets say @ 1400rpm, it will backfire ever 10 seconds or so. its more like a spit. when i throttle it from 650rpm it back fires immediately and i have to nurse it a little to get it going. adjusting the timing doesnt help to much and the carb id nice and richly black.

    any suggestions?
     
  2. woody

    woody Internet Fireman Staff Member

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    vacuum leak....spray carb clean around the motor while it's running and if it smoothes out, then try and pinpoint the leak.
     
  3. 3_puppies

    3_puppies SILVER Star

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    I'd check around the base of the carb. Were the surfaces clean?
     
  4. johnny

    johnny

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    all the mating surfaces are fine, and all the gaskets are clean and new.

    i only have 2 vacum hoses. distr. and pcv hose. both are fine with no leaks.
     
  5. johnny

    johnny

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    but i'll give your idea a shot, woody
     
  6. kruzrtek

    kruzrtek

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    You didn't mention if you had electronic ignition or a points style setup. If its points then you have to set the dwell at 32 degrees before you can set the timing properly. I had one in my shop a week ago that did the exact same thing with a dualjet on it. We thought it was a vacuum leak as well. No leak found!! Anyway it turned out to be a points completely
    pitted and in very bad shape causing the dwell to change 10+
    degrees and that of course changes timing.
    So, I would lean towards that!If I can give you any more details, just PM or email me.

    Kruzrtek
     
  7. toddslater

    toddslater SILVER Star

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    If after you done the above for vacuum leaks and checking the points.....and if it is still popping and spitting (non electronic ign only here) (and also rule out any issues with the dist cap arcing) put in a new condensor. When condensors go it will cause backfiring and spitting. Next stop on the ign side that could cause your problem is a bad ballast resistor. Last stop on the ign side is the coil itself. It is a systematic process of elimination, rule out vacuum leaks, fuel delivery issues, and ign issues.
     
  8. toddslater

    toddslater SILVER Star

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    Oh, almost forgot...so it sounds like you don't want your weber anymore....for the right price I'll take it off your hands. ;) Send me an email if you want to sell it.
     
  9. johnny

    johnny

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    slater, i'll sell you the webber email me @ johnnymcelmurry@hotmail.com.

    i've checked everything mention and no results. i did get the carb. to catch on fire. that was neat.

    is it possible that its just the carb. thats bad? i just dont see how that could be the case. all i did was swap the two, and when i put the holley back on it took a dump. i haven't checked the ballast resistor though, what's typical when that goes out?
     
  10. Mace

    Mace rock scientist.. Staff Member s-Moderator

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    You plugged the big vac tube on the back of the carb right?
     
  11. johnny

    johnny

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  12. toddslater

    toddslater SILVER Star

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    johnny,
    the popping, backfiring, and general unexplainable irratic behavior are all possible with a failing ballast resistor...and you've got mail.
     
  13. kruzrtek

    kruzrtek

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    Hey johnny,
    This is kruzrtek. I was wondering if you had chacked the
    points in the distributor. The contacts should look god and smooth. Also I don't believe there is going to be an issue with a ballest resistor because there shouldn't be one! The wire
    that goes down to the distributor will, in most cases, come from the negative side of the coil. These things are critical
    to inspect, because one little mistake and you miss the
    whole problem and you start over again!
    PLEASE e-mail me and leet me know any questions you may have. I know I have seen this, and I know wwe can fix it!
    Or did you??

    Kruzrtek
    kruzrtk@xmission.com
     
  14. johnny

    johnny

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    thanks to everyone for all the replies. honestly

    now i have a spare (spair) coil for back up and it does the same thing all the time, so i know its not the coil. i pulled the dist. and filed the points, cond., etc. so everything makes good contact. the points i replace as well as the cond. , so they are all fine. i pulled apart the dist. to make sure it was ok and it was. all my wires are fine and the plugs are good too.

    it should be noted my holley is fairly beat. all the hoses are fine.

    now about the ballast. why would it go bad, during an exchange of carburetors? i don't think it did. why would it? i thought of putting the webber on and seeing the results, but since i'm in college and have grades, papers, exams, etc. i'm short on time.

    i want my ride back, i've spent hours on this. i love my crusher, i love to be seen driving it, i want it to work again.

    i know its not the distributer b/c i've done everything possible w/ it.

    could it just be that the carb. kicked the bucket????
    more suggestions please.

    go Bush, I'm in full support....
     
  15. toddslater

    toddslater SILVER Star

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    For 10 points and a trip to Cleveland can Kruzertek identify the rectangular item in this photo
     
  16. toddslater

    toddslater SILVER Star

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    Since you've checked you points and condensor...by default you have a non electronic ignition and therefore most assuredly should have a ballast resistor. (the rectangular dodad from the above photo). Also, it wouldn't hurt to put in yet another new condensor...I've had them bad right out of the box. If all the thing from the ignition side have been double checked...an outside shot, and the last I can think of on the ign side, is the switch itself. I had one go bad, found it by jiggling it and making the engine cut out.

    When you had you 32/36 on, did you have a fuel pressure regulator on it ?