Hard to Start When Hot.....Carb?

Discussion in 'Troubleshooting & Diagnosis' started by gordonquixote, Aug 16, 2009.

  1. muscl car

    muscl car Veteran Member Lifetime Gold Member

    gordo it sounds like fuel puddling into the intake when the engine is warm and is caused by fuel dripping from the boosters or a sticking float or bad needle/seat assy . next time you drive the camaro get it nice and warm then park it ,but before you leave it pull the air cleaner off and see if you can notice fuel dripping from the boosters or notice vapor coming out of the throttle plates

    if this is noticeable then you've got a problem with percolation and you'll need to check the float level and either clean the needle/seat or replace them .also just adding insulation around the fuel lines were it's in contact with a heat source will help alot



    you can wrap your fuel lines with this and it will insulate the fuel lines from the high underhood heat and both will insulate up to 2000 deg

    http://www.summitracing.com/parts/THE-14010/

    [​IMG]


    http://www.summitracing.com/parts/DEI-010474/


    [​IMG]


    you can also put this on between the carb and intake and it will keep the float bowls from percolating .you can also have this treated with high heat coatings to help decrease temps

    http://www.summitracing.com/parts/HLY-108-70/

    [​IMG]


    you can always use this ....... a cool can that allows dry ice or regular ice to help cool the fuel down before entering the carb ,this also increases hp from a denser fuel charge into the motor

    http://www.summitracing.com/parts/MRG-1350/


    [​IMG]
     
  2. muscl car

    muscl car Veteran Member Lifetime Gold Member

    found this on copo's website

    Q. Flooding or have fuel dripping on the throttle plates after engine shut down.
    A. Remove the needle and seat from the top of the bowl and take compressed air and blow out all specs of dust/dirt. One spec will stop the needle/seat from stopping the fuel from leaking. Did you also remember to add a gasket and the small piece of steel with a point at one end under the squirter?

    Q. I have a wet spot of fuel overnight on the bottom of your throttle plates.
    A. This is an actual problem I had and was stumped for a while. I removed the fuel bowl and metering block and noticed that the power valve was loose. Place the block in a vise with wood on each side of the vise jaws and tighten to the following specs.
    [​IMG][FONT=book antiqua,times new roman,times]for power valve with multiple drilled fuel opening, torque to 40-50 inch pounds.[/FONT]
    [​IMG][FONT=book antiqua,times new roman,times]for power valve with 2 rectangular fuel openings, torque to 100 inch pounds
    [/FONT]
     
  3. markw

    markw Veteran Member

    816
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    Jun 6, 2009
    Illinois
    Are you running an aluminum manifold with the heat riser passages open? You can close the passage off and it might help the problem, but then you may have driveability issues until the manifold warms up. I've seen some of those restrictors with about a half inch hole in them to cut down the flow of exhaust gas in the passage and keep the manifold a little cooler. Any insulator under the carb is better than none. Fuel line not near any heat?
     
  4. 71RS/SS396

    71RS/SS396 Veteran Member

    2,557
    16
    Aug 26, 2008
    Wake Forest NC
    I had this problem with mine too. I have a flowmaster transverse muffler and it was heating up the fuel in the tank, I wrapped the muffler with DEI heat blanket and it made it much better,but I think this crappy fuel we have today is part of the problem.
     
  5. grasmo

    grasmo Veteran Member

    892
    0
    Dec 21, 2005
    tallahassee, fl
    try dropping the float level just a little. as the fuel absorbs the heat, it could be expanding enough that it's coming out of the boosters. the boosters are the lowest "dam" point.
     
  6. Jim Stokkeland

    Jim Stokkeland Administrator Lifetime Gold Member

    LOL, had the same problem with mine Gordo (still do), mine was a timing issue. If I drove the car at all, it would fire right up, everytime, all day. The guys that tried to fix the paint for me in 07 adavnced the timing for me...it did run a lot better, was was a little harder to start. I only had to kik it 3 or 4 times tho.
     
  7. ezcruisn71

    ezcruisn71 Veteran Member

    239
    0
    Jun 2, 2006
    SE, Michigan
    I have the same problem with mine. Three pumps of the pedal when cold. If you shut it off when it is hot and you only wait a few minutes to restart it will start right up no problem. If you let it sit for 30 minutes to 1 hour then it seems like it is flooded. Have to hold it to the floor to start it.
     
  8. Z28SSRS

    Z28SSRS Member

    95
    5
    May 2, 2009
    Nevada City, CA
    I can't remember when my car first started doing this. I know it never did it when it was new. Based on my best memory I would estimate my '78 started doing this in the late 1990's. Don't know when they started adding ethanol to fuel here in California. Have had my Q jet rebuilt in 2005. It's not as bad now as it was prior to rebuild, but still does as other posters have reported. I still blame it on today's fuel.
     
  9. Gary S

    Gary S Administrator Lifetime Gold Member

    20,634
    181
    Apr 14, 1999
    Bismarck, North Dakota
    I think you may have hit in most of the problem. Ethanol will do this and lots of other problems. I refuse to use ethanol in my cars because it always causes some kind of drivability problems.
    I have 3 old vehicles with quadrajets. They all start perfectly warm, cold, or half-warm all of the time using real gasoline.
    Since I refuse to put ethanol in my tanks, it always amazes me at the problems other people have with Qjets. The Qjet is and always has been the best and most reliable carb built.................if you don't mess with it, and if you feed it good fuel.
    The quadrajets are not alcoholics, so why would you feed them corn liquor? Drink it yourself. It does more good for you than it does for your car.
     
  10. gordonquixote

    gordonquixote Veteran Member Lifetime Gold Member

    3,019
    4
    Jul 18, 2006
    Tallahassee, FL
    Great ideas everybody. The next weekend I drive the car - I'll know what to look for.

    I tell ya - I only get gas once every month or two.....I wonder if the ethanol is turning into water. Maybe Stabil would help?

    Again, thank you everybody - I feel better that it's not just me. It sucks because people stare at the car wherever it is.....and then I have to hold the start button down to get it to crank. F'n hate that!
     

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