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By MikeLongIsland - 16 Years Ago
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Hi Guys ! I have a 1956 f100, 272, 2bbl, when i turn it off fuel seeps out of the bottom of the carb. I thought it was a carb problem, so I ordered a nice rebuild from the folks at vintage speed. Same problem still exists. I changed my fuel pump to a holley mechanical, which puts out 7.5 lbs of pressure, could this be my problem, too much pressure?
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By PF Arcand - 16 Years Ago
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Is the 2 Bbl carb an early 3 bolt type, or 57 & later Holley 2300 type?
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By MikeLongIsland - 16 Years Ago
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3 bolt, ford built by holley a 94 i believe
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By sundance241 - 16 Years Ago
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I believe that runs on about 3.5 lbs of pressure ....Sam
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By MikeLongIsland - 16 Years Ago
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So the fact that I have 7.5lbs would make it push out of the base after shutdown?
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By sundance241 - 16 Years Ago
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Mike , what i installed on my 56 is an adjustable reulator , then you are able to adjust the way you like , also i am not so sure the gauges all read the same !!!! I installed in line in front of the carb , made a simple bracket to hold up off the intake .......works good .................Sam
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By MikeLongIsland - 16 Years Ago
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Thanks Sam, seems that most regulators are designed for electric fuel pumps, and have a return. I wonder if installing a non-return type would be creating too much backspressure for a mechanical pump Mike
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By PF Arcand - 16 Years Ago
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Mike: What was the reason for installing a 7.5 Lb pump? If you have the original & it's in working order, put it back on temporarily & try it out..
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By PF Arcand - 16 Years Ago
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Mike: What was the reason for installing a 7.5 Lb pump? If you have the original & it's in working order, put it back on temporarily & try it out..
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By MikeLongIsland - 16 Years Ago
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The original pump and entire fuel system was polluted beyond repair, even changed the tank
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By MikeLongIsland - 16 Years Ago
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Heat Rizer is gone in lieu of headers, and the float is working properly, all I could think of was the pressure was pushing the fuel past the seat
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By charliemccraney - 16 Years Ago
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Well, do mechanical pumps have check valves? That would hold 7.5psi for a time and heat soak could cause the pressure to increase. Otherwise, there shouldn't be any pressure once you shut it off.
Do you have a heat insulator between the carb and manifold?
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By MikeLongIsland - 16 Years Ago
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if a gasket is an insulator I do
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By MikeLongIsland - 16 Years Ago
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I don't think heat is a factor, was only running in the driveway for 20 minutes tops
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By pegleg - 16 Years Ago
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Mike, I've been halfway following this. Got two questions that may, or may not, be relevent! Can you determine where the fuel is coming from, Seeping out the gasket between the airhorn and body would/ could indicate boiling, a leaking needle, or float level too high. Second, try covering the front of the carb while it's running, to see if the air from the fan is evaporating the fuel while it's running. Maybe the same condition exists off or running, but the airflow dries it before it becomes noticeable.  Third (I know I said two, but I just thought of this) are you sure the fuel lines aren't leaking at the carb. This happens a lot, but you might only notice it until the residual pressure drops. Last, shut it off hot and watch the inside of the carb to see what or where it drips.
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By timmy4 - 16 Years Ago
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When I rebuilt my carburetor I bought a power valve from vintage speed 772 778 0809 because the the ones in the rebuild kits are the wrong ones for those carburetors. Vintage speed told me that he had to machine his own power valve for those carburetors because the print for the original version got lost and the version of the power valve they put in the kits are for the newer ford carburetors and that will cause it to leak out of the float bowl when the engine is not running
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By MikeLongIsland - 16 Years Ago
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Would Have responded sooner but I was enjoying the Mountains of Vermont this weekend. The fueel seems to be running out of the base itself, only on the right side. The Carb was rebuilt and purchased from Vintage speed, but since this is the same problem as the last carb it makes me look elsewhere, I have a fuel regulator comming in the mail this week for it, thats my next plan of attack. Hope all had a great weekend, Mike
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By paul2748 - 16 Years Ago
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Way too much pressure. Get a regulator and set it at 2.5 or 3.0 lbs. You are overpowering the needle and seat with so much pressure. I doubt any of the other things are a cause if the carb is otherwise good. I would go back to a mechanical pump and a regulator. I tun a 3 x2 set up, regulator set at 2.5 lbs and no flooding problems.
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By MikeLongIsland - 16 Years Ago
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cool Tom ! I have been going there since i was a kid,friend has a house outside of Wilmington. Maybe we could meet someday, my wife loves your car (the avitar you show). Mike
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By Ted - 16 Years Ago
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Mike. You said Holley 94’s on the 3X2 setup so I’ll repost this about fuel pressure from a past thread. http://www.y-blocksforever.com/forums/Topic22513-3-1.aspx Ted (2/20/2009)
The fuel pressure spec for the Y is rather broad in that it’s 3½-5½ PSI so technically any of the Y-Block fuel pumps should interchange without much issue. With an electric fuel pump and modern carb on a Y, I’ll aim for 6-6½ PSI for both the street and performance but less than this is not a show stopper if the volume is adequate.
I’ll add that the Stromberg 97’s are supposedly sensitive to high fuel pressures and for dyno testing those, I’ll limit fuel pressure to 3½ PSI. I just haven’t experimented with higher than this for the Strombergs but plan to do so in the near future as there were some questions regarding fuel supply at the higher rpms with the 3½ PSI fuel pressure setting during a recent test session. But for the Holley 94’s I’ve run with as much as 6½ PSI without issue. Float levels being too high would be an easy item to check in your case.
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By MikeLongIsland - 16 Years Ago
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Thanks Ted, but in this case it is a single 2bbl, with holley mech fuel pump rated at 7.5 lbs. I havn't dared try the 3x2 yet, figured i'd get it running right first. Mike
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By MikeLongIsland - 16 Years Ago
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Well added a fuel pressure regulator, rechecked needle and seat and float level. The truck runs great, but get it warm, shut it down and fuel still oozes out, different location this time, drips off the accelerator linkage, I am at a loss. Is a 1956 f100 fuel tank supposed to be vented, because mine is? Mike
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