Ford Mustang Forum banner

Edelbrock Secondaries Lock

7117 Views 8 Replies 3 Participants Last post by  kenash
Okay so I have an edelbrock 1406 and I have a question about the secondaries. When I manually pull the throttle when the car is off, the secondaries only open slightly because a lock plate hooks around a notch on the secondary shaft and keeps them from opening. The rebuilt kit i bough calls this plate the "lockout arm" if i move the arm out of the way manually, when i push the throttle, the secondaries open all the way. I'm confused as to why this is happening.

Ive seen online that it has to do with vacuum pressure and the electric choke and that the secondaries will open when the engine is under load. Can anyone explain to me how this works and how i know that its working properly?
1 - 3 of 9 Posts
First off I am not a edelbrock expert, but I've worked and rebuilt a lot of carbs in my day, so I will take in generalities. IF the choke is not fully open, the secondaries are locked out. Once the choke is fully open, then depending on the design of the carb, there is usually a lever or pin that touches the secondaries throttle lever from the primary throttle rod lever, this helps finish closing the vacuum secondaries when you release the throttle, if the engine is not running the vacuum secondaries will close all the way if you operate the throttles manually, it the engine was running like when you are driving and you let off the gas the engine would run fast around 1500-2000rpm or more, if it was missing or broken. I do this to check the integrity of the secondary diaphragm and the path the vacuum takes for it, and if it is possible to get my finger on the secondary pick-up tube (this is the tube in the venturi that leads to the secondary diaphragm), with the engine off, I open the throttle and hold, then I open the secondaries and hold, then I plug the tube in the venturi, and let go of the secondary throttle and see if it holds vacuum, if it does the secondaries will stay mostly open, if there is a leak, it will close. The hesitation, can be caused by several things, (like float levels, power valve leaking, secondary metering jets getting plugged at little) and the accelerator pump settings or the accelerator pump is getting worn out. Good Luck.
See less See more
Here is a link on your carb, if you look at fig 6 this is the lockout arm, and the other piece is the fast idle cam for the choke, the choke is not just the butterfly at the top of the carb.

I hope this clarifies what I am talking about. Good Luck.
Can you take a picture of the lockout arm on your carb, or does it look like they installed something backwards? Maybe some of the guys or gals on this forum that are running the edelbrock, can give a hand. Good Luck.
1 - 3 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.