2x4 high idle speed problem

Author	Message
NoShortcuts	Posted 11 Years Ago
Supercharged Group: Forum Members Last Active: 2 Years Ago Posts: 1.4K, Visits: 179.6K	In August 2013, Forum member BLACK57ECODE in Australia posted a question about his dual quad set-up. Since then, Tony and I have been in regular correspondence and with Felix Natoli's help have remedied his originally reported incorrect throttle linkage problems and some other component irregularities, too. When purchased last year, this '57 'E' came with two matching number '56 Ford single quad application Holley 4000 carburetors installed in place of the original '57 'E' Holley 4000 carbs. The following modifications have been made to the '56 Holleys to improve their performance in the 2x4 configuration ... installation of secondary vacuum signal balance tubes, installation of yellow secondary vacuum diaphragm springs, modification of the rear carburetor base (per Ted's web site info) to obtain the correct vacuum signal for the '57 'E' distributor, both spark control valve ports blocked, and the no longer used '56 Loadomatic distributor vacuum take-off ports blocked on both carburetor bases. Since doing the above modifications, totally disassembling both carburetors and installing rebuild kits, Tony NOW has an elevated idle speed problem that he did not have before going through the carburetors. OUCH! The possibility of a vacuum leak has been pursued with no success. NOTE: the carburetor kits used in rebuilding the carbs were supplied by Jon Hardgrove (The Carburetor Shop LLC, Eldon, Missouri). The kits seemed QUITE complete and were designated specifically for the Ford '56 and '57 2x4 application Holley 4000s. I was surprised that the kits did not include the secondary vacuum diaphragm springs. __________________________________ Is there anything different about the gaskets for the original 'E' carbs that might cause this high idle problem? Specifically, do I recall someone indicating that the vent holes are different on the fuel bowl cover for the '56 power pack and '57 'E' series carbs? Ideas as to what might be causing this high idle speed condition would be greatly appreciated! NoShortcuts a.k.a. Charlie Brown near Syracuse, New York
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*Hoosier Hurricane*	Posted 11 Years Ago
Supercharged Group: Moderators Last Active: 4 hours ago Posts: 3.7K, Visits: 322.7K	Were the throttle plates removed during the overhauls? If so, maybe one or more of them is not centered in their bore, causing the throttle to be held slightly open. How are the throttle shaft fits in their bores? Worn shafts and bores admit extra air as well as not letting the throttle plates close correctly. One more obvious thing. Are the fast idle cams holding the throttles open for some reason? Good luck. John - "The Hoosier Hurricane"
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NoShortcuts	Posted 11 Years Ago
Supercharged Group: Forum Members Last Active: 2 Years Ago Posts: 1.4K, Visits: 179.6K	THANKS for your reply, John. Yes, Tony indicates that he totally disassembled the carbs, removing the throttle plates and the shafts. I also thought of a reassembly error. Tony indicates that the throttle shafts did not appear to be worn AND he did not have the high idle speed problem before carb teardown for rebuilding. Failure to be careful in centering the throttle plates in the primary and secondary bores when re-installing them definitely could could cause a throttle plate closing problem and therefore an elevated idle speed. I've always used a bright light source (light bulb) on the opposite side of the throttle plates when centering the plates before tightening the screws to the throttle shafts. __________________________ In ordering the carb kits for Tony, I ordered the ones Jon offered specifically for the original power pack and '57 'E' carbs because I assumed that the power valve diaphram springs would be correct for the application instead of having to remove 2 or 3 coils from each single quad application kit. I also thought that the correct springs would be supplied for the secondary vacuum diaphragms. Tony ended up purchasing the correct secondary diaphragm springs from Holley in their 4150, 4160 carb performance tuning packs. The white springs yielded a stumble, the yellow a smooth transition for the secondaries opening on Tony's particular engine. __________________________ Tony's hoping for a simple fix before tearing the carbs down again. Something like a fuel bowl vent hole problems or fast idle cam linkage problems would be appreciated. Again, thanks for you input, John. -Appreciated. NoShortcuts a.k.a. Charlie Brown near Syracuse, New York
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*Hoosier Hurricane*	Posted 11 Years Ago
Supercharged Group: Moderators Last Active: 4 hours ago Posts: 3.7K, Visits: 322.7K	Thought of another possibility. The little wires that ride in the slots of the secondary throttle arms. If they are "opened up", making them longer, they can bottom out at the top of the slot and prevent the primary throttle from closing completely. John - "The Hoosier Hurricane"
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NoShortcuts	Posted 11 Years Ago
Supercharged Group: Forum Members Last Active: 2 Years Ago Posts: 1.4K, Visits: 179.6K	THANKS, again, John. It's hard to believe that Tony is in the middle of winter down under, now... In checking the movement of the throttle shafts with all of the intake manifold linkage removed, Tony has found one shaft is binding on the rear carb. He can't believe that he messed up in centering the plates on the throttle shaft, but realizes that we're all human. -It took both of us suggesting this to get him to look at it, John. That said, Tony KNOWS you have a lot more knowledge about this stuff than I do! You've also got him looking at the secondary linkage connecting pieces, too! Regards, NoShortcuts a.k.a. Charlie Brown near Syracuse, New York
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NoShortcuts	Posted 11 Years Ago
Supercharged Group: Forum Members Last Active: 2 Years Ago Posts: 1.4K, Visits: 179.6K	Follow-up... I got an email from Tony Thursday night from Australia. The misalignment of throttle plates WAS the source of the high idle speed on his 'E' set-up. Tony writes: "This time with glasses on and paying great attention to detail I could see light past the butterflies when they were fully closed." After first fixing the obvious throttle binding problem in the rear carburetor, he pulled the front carb to double check that everything was correct with that one as well. Although not binding, one set of throttle plates were incorrectly positioned in that carb, too. After reassembly, idle speed is now down to 600 from the 900 to 1200 he was struggling with. Tony's doing a happy dance now and writes: "Thank you and Hoosier Hurricane for all your advice and thoughts. I am indebted." _____________________________ I believe that this Forum has helped a lot of people over time. Thanks to all who contribute or have contributed! NoShortcuts a.k.a. Charlie Brown near Syracuse, New York
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2x4 high idle speed problem

2x4 high idle speed problem

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