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Just went to a sheetmetal intake and two 9377's modified by Nickerson Performance, (bought these used), idle is good with the idle mix screws out 3 1/2 turns. This seemed like a little more that I'm used to. Runs good WOT with egt's all very close. The main problem is staging, we run a pro tree and when I transition from idle to wide open throttle the engine will die. If I run a sportsman tree where I can take a little longer bringing the RPM up its fine. The 50cc pumps are adjusted at .010-.015 from bottom, the squirters are #35. The carbs are supposed to flow 1250cfm. This is on a 700 inch motor. The mechanical linkage that I run definately opens the throttle blades quickly whitch adds to the problem. When the car dies it will start up easily and does not blow a bunch of black smoke, so I'm assuming its just going lean. Any thoughts?
 

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Does it still have the intermediate circuits? The problem is in the transition from idle circuit to mains. If floats are too low it will do it as well as. does it have 6 air bleeds per side still?
 

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Make sure that the pump shot is timed to the "snapping" of the throttle - you can discharge the shot too slowly,too quickly,too much or too little - air is always there- it is the fuel timing that is missing.
Try preloading the shot first.
Smaller squirters will extend discharge and vice versa.
 

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With twice as many Idle circuits with dual carbs vs single, changes have to be made to keep it from being rich at idle. It may be that it was set up too lean to work for you but may have worked on the engine they were on originally. I would look at the idle jet and idle air bleed sizes. It is a bit different with 2 carbs, it has to be lean enough at idle yet rich enough to feed the transition circuit. The idle jet needs to be smaller than a single Dominator to keep the idle circuit from being too rich, a single carb being around .036 - .040. The idle air bleed also needs to be smaller to make sure the transition circuits are active long enough, a single Dominator would be around .068 - .073. A good starting point for duals would be around .035 on the idle jet and .052 on the idle air bleed. It may be a little rich, if you go up on the idle air bleed more than about .010 and it's too rich go down a few on the idle jet. If you gan get your mixture screws in between 1/2 & 1 1/2 turns out you should be pretty close. As far as dying going WOT, if it's truly lean you can try going up on squirter size. A good test would be to put fresh plugs in, do a burnout, and back the car up and pull the plugs. If they are dark, you may have the intermediate hurting it. All this is assuming you have a known good ignition, optimized timing, and no mechanical issues. Also, buy some brass set screws and a drill set for your idle jets and idle air bleeds to make your own, cheaper than buying Holley stuff. McMaster-Carr is a great source for the set screws.
 

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on my nickerson carb two out of four idle feed tubes had fallen off in the blocks. when the third fell off it wouldnt idle at all. definitly sounds like at the least your idle circuits need to be rewroked like stated. if the mixture screws are 3.5 turns out and your still not getting enough fuel the ifr's need to be increased and the iab's decreased. i was having all kinds of issues with the transition on my nickerson dominator so i sent it to pat at pro systems. hope to have it back in a week or two.
 
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