Holley carb and engine not running quite right

Discussion in 'Engine Topic' started by Elfmaze, Aug 13, 2019.

  1. Elfmaze

    Elfmaze Veteran Member

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    Hey guys,
    Starting to tear into this one.

    Carb: Holley 3310-11
    block: early 70's 4 bolt 355ci
    Intake: performer EPS 2701
    Exhaust: shorty headers
    Dizzy: flame thrower HEI
    Cam : mild Crane cam (pending cam profile from previous owner)
    Trans : 200R4 built by Janis Transmissions in Akron OH

    So car is ripping through fuel, which is to be semi expected. But its also fairly slow only hitting 0-60 times of around 8-9 seconds. semi hard to start but with about 1/4 throttle can get it reliably started, Wreak of gas smell pulling it into the garage. Origionally thought it was the cars origional 305 so dismissed the performance but on realizing it is a 350 It should be doing better.

    Started looking into the carb floats are set right but fuel pressure is a bit high at 8-5 or so. vaccum is reading only about 11-13 in at idle. mixture screws did not seem to have much effect. whats my next move here?

     
  2. muscl car

    muscl car Veteran Member Lifetime Gold Member

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    Lower fuel pressure to 5.5lbs then check power valves to make sure they're not blown
     
  3. 77 cruiser

    77 cruiser Veteran Member

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    Vacuum leaks, power valve blown
     
  4. Elfmaze

    Elfmaze Veteran Member

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    So get an inline regulator, and if the power valve is blown it would leak fuel through at all manifold press leading to the overly rich?
     
  5. Elfmaze

    Elfmaze Veteran Member

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    I don't know where vac leak could happen... only has the power brakes on vac lines. the diagnostic port is capped and the other goes to the dizzy
     
  6. Elfmaze

    Elfmaze Veteran Member

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    I did Holleys procedure at the end of the video. I CAN kill the engine with the mixture screws, video says the power valve is "not" blown per that rubric.

    2:40
     
  7. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    You would be amazed where vacuum leaks can occur. I use an unlit propane torch to check for vacuum leaks, intake manifold gaskets are pretty common leak points.
     
  8. Elfmaze

    Elfmaze Veteran Member

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    Ok, should be pretty easy for my to rig up a smoke machine and push some smoke back into the vac line, a glove over the carbs intake barrels should give the pressure I need right?
     
  9. jeff swisher

    jeff swisher Veteran Member

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    look down the carb at idle ..it should not be dribbling any fuel at idle from the boosters.

    Timing curve will be a big player in the MPG and bad exhaust smell arena.
    You need to have in my mind at least 18 and some engines like much more like 24 initial timing at idle.
    If you have 10 it will cause you to open the throttle plate farther which does affect idle screws.
    What is your idle timing now?
     
    Dave Nelson likes this.
  10. 2ndGenCrazy

    2ndGenCrazy Veteran Member

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    Yes, absolutely ALWAYS verify ignition BEFORE touching the carb.
     

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