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Flathead Running Problem

Discussion in 'The Hokey Ass Message Board' started by T_Bird Guy, Jul 27, 2009.

  1. T_Bird Guy
    Joined: Oct 6, 2006
    Posts: 225

    T_Bird Guy
    Member

    The flathead in my 1947 Ford is having some trouble and I think I have narrowed it down to a fuel issue. The flathead has been rebuilt about 3000 miles ago. It is 59A that has been bored 60 over and stroked with a 4 inch Mercury crank. It has a mild cam and running on 12 volt. It has stock heads, intake, carb and fuel pump. The distributor has been rebuilt and the car rewired. The fuel line is rubber from the tank to the fuel pump and runs inside the frame. The problem is after about 20 minutes of driving the engines starts to hesitate. Then I lose rpm and speed. I can put it to the floor and it won't gain rpm. Also have tried to rev it up with the clutch in and it does not increase rpm. Then the engine will just die and not restart. I have checked the carb with the air cleaner off and when I hit the throttle I see it adding fuel. I have been thinking it is vapor locking and the pump is not able to pull fuel to the carb. I have removed both the inline fuel filters that were on the car. This is where I am at now. I would like some suggestions to aid in finding the problem.
     
  2. uncle max
    Joined: Jan 19, 2006
    Posts: 905

    uncle max
    ALLIANCE MEMBER

    Just a guess, but probably the rubber fuel line is collapsing as you drive it. Definitely go to a steel line.
     
  3. JohnEvans
    Joined: Apr 13, 2008
    Posts: 4,883

    JohnEvans
    Member
    from Phoenix AZ

    If it squirts fuel when you work the throttle doubt that it is a fuel issue. Quite possiably a bad coil or condensor. Being it is 12 volt do you have a resistor before the coil and what coil are you using?
     
  4. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    Classic bad coil symptoms...condensers act about the same.
    Also, when checking carb from throat give several squirts...it is possible for fuel bowl to be near empty and pump well still wet.
     

  5. Agrre with Bruce, check coil/condensor.

    Eliminate one at a time till it improves and you've found it.

    Rat
     
  6. six pack to go
    Joined: Aug 2, 2008
    Posts: 1,938

    six pack to go
    Member
    from new jersey

    I just changed the condencer, cap, rotor and points in my 1950 and felt a noticeable difference...didnt have that problem like yours but would pop ans sputter...try that as well...
     
  7. T_Bird Guy
    Joined: Oct 6, 2006
    Posts: 225

    T_Bird Guy
    Member

    My rubber fuel line is fairly new. I am running a coil that has a built in resistor. But if the coil is bad it would be the third coil to go bad in over a year.
     
  8. Da Tinman
    Joined: Dec 29, 2005
    Posts: 4,226

    Da Tinman
    Member

    is the vent open on your fuel tank?
     
  9. jetmek
    Joined: Jan 12, 2006
    Posts: 1,846

    jetmek
    Member

    add a ballast resistor anyway...fixed one recently that was 12v with "no external resistor reqd" coil it would get hot and run bad. a ballast fixed it good as new.
     
  10. T_Bird Guy
    Joined: Oct 6, 2006
    Posts: 225

    T_Bird Guy
    Member

    Would that reduce the voltage too much to the distributor?
     
  11. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    Throwing a random resistor at a random coil before figuring out for sure coil is the problem...yes, great idea!
    First, runnit til it stops and either throw on just about any spare coil you can get and see if problem stops...or chill down existing coil on the spot by putting it into a bucket of cold water for a couple of minutes, wipe it dry, and see if you can put it on and drive away til it heats again.
    If it IS the coil, get a known system that will work. Go to a good store, maybe NAPA, and get the good coil of the 2 or so they offer for each application (Echlin brand) or the good choice from Standard/Blue streak. No mystery suppliers.
    Get a coil from a known application (Repeat after me..."I have a 1968 Mustang 289 with power steering...") AND buy the resistor and condenser for the same car. Not all coils are the same, not all resistors are the same value. Randomness not good here.
     
  12. T_Bird Guy
    Joined: Oct 6, 2006
    Posts: 225

    T_Bird Guy
    Member

    I have a Standard/Blue Streak UC15X coil on it now and I work at an auto parts store so that is the brand that we carry. It is a universal 12 volt coil that does not require a resistor. Would the location of the coil effect it heating up? I have it mounted in the stock location.
     
  13. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    Shouldn't be any hotter than most coil locations, and is good brand.
    Another quick coil test: Run til you get well into the trouble. Disconnect coil...jumper switch side to battery direct. Connect distrib side to a jumper, repeatedly touch other end of jumper to head stud and release...at each release you should get a spark from secondary wire, held near head. If spark is yellow and thin, you have the coil trouble I am describing. If fat and blue, coil isn't the problem. On a '47 Ford, you will need a spare secondary wire as well as the two jumpers to make test...
     
  14. JohnEvans
    Joined: Apr 13, 2008
    Posts: 4,883

    JohnEvans
    Member
    from Phoenix AZ

    As a parts guy ya oughta know just 'cause it's new don't mean squat. Try another coil/Cond . And like Bruce said work the throttle 3-4 times to make sure you have fuel in the bowl and not just in the pump circut.
     

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