Duel carb linkage / Idle

Duel carb linkage / Idle

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By Philip - 10 Years Ago

I've built another set of factory E carbs for my 57 OD car. They idle @ 900 RPM's but if I push down on the primary throttle shaft level assembly it closes the secondary throttle shaft assembly and the engine will idle @ 500 RPM's. I just need to bump it and it stays down until I rev the engine and the idle is back up to 900. The fast idle cams and the idle screws are not in play and I've synchronized the linkage per the Ford guide book. As you can see by the photo @ 900 RPM's the linkage on both carbs secondary have enough movement to idle the engine @ 500 RPM's so the linkage is not binding. A light spring on the primary lever assembly would bring the idle down but this is a farmer fix. My question : Is vacuum suppose to keep the secondary plates closed until throttle acceleration? Any helpful suggestions would be appreciated. Philip in Ohio

By DryLakesRacer - 10 Years Ago

Sorry to hear of your problems. Even tho I do not use the Holleys on my dual quads I had the same problem. I felt it came from using the verticle single spring on the stock single carb linkage. I increased the tension on the spring and the idle did lower. I also took off both carb to make sure the throttle plates were sealing and there was no binding. I took extra care in tightening the base nuts on the studs. I do use 1/4" phoenolic plates under each card and new gaskets.
After some driving I felt the foot pressure on the throttle pedal was just too much. I went to lighter spring on the linkage and your"farmers fix" on each carb with an additional light spring. It sure is easier to drive now. Good luck

By DryLakesRacer - 10 Years Ago

One other thing you should use a synchronizer when you get the close. I made one for WCFB's by following the Google search " DYI carburator synchronizer" I needed an additional adapter from the large to the smaller top. I used sealed them with RTV. You may need a spacer because the top of Holley is so tall. Good luck.

By Philip - 10 Years Ago

Thanks for your replies. If you belong to the CVA club and plan on going to their convention in Dayton Oh. I'll look you up. One thing you might check on your car is making sure the accelerator linkage coming through the fire wall isn't bottoming out keeping the linkage from completing retracting. I've had this problem happen to me. This is a factory E car and I believe I have the right material under the carbs but I'll google your info for more information. I'm trying to keep this car as original as possible. One of my car friends thought that vacuum might be a factor so I'm looking for a yes or no answer to that possibility. Philip in Oh

By DryLakesRacer - 10 Years Ago

Thanks for your reply.My pedal floor linkage is is free and clear. I live in Southern California so Dayton is bit too far. Not much happens here in SoCal with the CVA. I was invited on a cruise one time a few years back but I was still sorting out the car and could not do it. I have written them an article for the FOMOCO Times but need to take some photos first.
If you search here you can fine many photos of my dual quad installation. It is the best thing I ever did to the car. Ford never it at the factory in 56 but I'm sure glad they made it available at the Dealer Parts Counter. Good Luck..JD