Hey guys I have a few basic questions.As some of you all know i had a motor swap and went with a 351W carb settup.My settup consists of a dart sportsman block bored 0.30 dart cylinder heads victor junior intake Fms roller rockers and all the internals are forged.Im running an accel distributor also.Ok so the carb that i had on my 351W a few months back was sold because i wanted something better.So i went with a quickfuel750 mechanical secondary carb and i just want to know some basics.The car runs and idles but at WOT it bogs then clears up.I think all 4 idle/air screws are set at 1 1/2 turns. The primary float has the fuel level sit right above the bottom of the sight glass. Is that to low or should i bring it up to the middle of the sight glass?My secondary float is set alot higher and the fuel sits just a little bit below the very top.Now is that to much for the secondary?If someone can give me the proper tuning specs of the carb i would so appreciate it.Also the bogging at WOT is that to much fuel?Is my car running rich? Like i said it bogs for about 2-3 seconds then clears up.Also when i start the car and drive it for about 2-3 minutes after then engine being cold it has very slow take off like it wants to stall out.This usually happens when i come to a stop and then go giving it gas it wants to die but i keep it running.Anytime after the 5 minutes of the car being warm it takes off good with no problems no bogging but then again i get the bogg/hesitation at wide open throttle for about 2-3 seconds.Its quite annoying and i figure it just might be a stupid problem so if anyone can help me please thorw in the advice.Thanks again guys for all who help.
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1987 Mustang Gt,Primer Black: 4 inch Ram Air Hood,351W bored 0.30 over,Holley 750 double pumper with 50cc accelerator pumps,Edelbrock victor jr intake port matched to Dart cylinder heads,Crane cam 630 lift,Accel ignition,msd coil,Msd 6AL box,Underdrive Pullies,Bbk long tube Headers,Flowmasters with dumps,Zex wet kit 125 shot,Full set of Autometer Gauges:Fuel level,Water temp,Volts,Oil,Air/Fuel,Vacumn/Boost, Subframe Connectors,Aluminum Driveshaft,Rollcage,Weld Draglites 5.5 Fronts 10.5 Rears
Cold engine/ intake manifold-- Fuel condensing into droplets and settling on the bottom of intake manifold. Normal until warm up.
Bog on acceleration--- A rich condition will show a black puff of smoke from exhaust at time of bog. Lean, no smoke. Go to a smaller squirter on the secondaries, try two sizes down if, rich condition. Two sizes up if lean. Make sure secondary accelerator pump correctly adjusted before doing anything. Secondary power valve must have a higher opening point than the highest manifold vacuum attained during flat out acceleration. If not the case, power valve will close and engine will run lean. A bad thing.
There is much more to tuning for this condition, jet sizing, accelerator pump cam adjustment, to name some issues. I'm not sure about your float settings because I'm used to the Holley settings without the window. You need to find the correct spec. for this before anything because float settings have a huge effect on carb operation.
If you are running a carb you need a book on it because carbs are a complicated subject and the more knowledge you have the easier it will be to tune.
Hey man thanks for the reply.I used a holley for my last carb and i believe it has 50cc Accelerator pumps.The quickfuel im using now has 30cc.For the sight glass i never had any on my holley but my floats were set both at the bottom.Now for my quickfuel my secondary float is alot higher and sits almost at the top.My primaries sit at i believe the bottom of the sight glass.When im at WOT i dont see any black smoke.My primaries and secondaries seem to be opening at WOT when im under the hood.I really havent got a clue what is causing my 2-3 seconds of bog/hesitation at WOT when im on it.Like for instance right before my gas pedal is completelly in thats when the bog comes and if i stay on it it goes away.Its kinda akward.I mean the problem correctsd itself but that 2-3 seconds would not help in any racing at all.any more info is great. thanks again
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1987 Mustang Gt,Primer Black: 4 inch Ram Air Hood,351W bored 0.30 over,Holley 750 double pumper with 50cc accelerator pumps,Edelbrock victor jr intake port matched to Dart cylinder heads,Crane cam 630 lift,Accel ignition,msd coil,Msd 6AL box,Underdrive Pullies,Bbk long tube Headers,Flowmasters with dumps,Zex wet kit 125 shot,Full set of Autometer Gauges:Fuel level,Water temp,Volts,Oil,Air/Fuel,Vacumn/Boost, Subframe Connectors,Aluminum Driveshaft,Rollcage,Weld Draglites 5.5 Fronts 10.5 Rears
The fuel level in a Holley, which I think the quickfuel carbs are pretty much just a fancy Holley, is supposed to be even with the bottom of the sight in both the primary and secondary bowls. This is according to the instructions that came with my Holley. If its not the float level and the accelerator pumps are adjusted correctly, then it may be that the secondary linkage is not set properly. Did you not get a instruction manual with your carb that gives you tuning tips?
I received a calibration sheet with the basics about the carb and so fourth, the only info that it really noted was about the air fuel screws being 1 1/2 turns out from seated.Other then that does not say where the fuel is suppose to sit in the sight glass in the primary and secondaries.I was told i might need to adjust my pump cam?Im not sure which 1 though so any ifno will help
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1987 Mustang Gt,Primer Black: 4 inch Ram Air Hood,351W bored 0.30 over,Holley 750 double pumper with 50cc accelerator pumps,Edelbrock victor jr intake port matched to Dart cylinder heads,Crane cam 630 lift,Accel ignition,msd coil,Msd 6AL box,Underdrive Pullies,Bbk long tube Headers,Flowmasters with dumps,Zex wet kit 125 shot,Full set of Autometer Gauges:Fuel level,Water temp,Volts,Oil,Air/Fuel,Vacumn/Boost, Subframe Connectors,Aluminum Driveshaft,Rollcage,Weld Draglites 5.5 Fronts 10.5 Rears
Like Chuck mentioned previously, float settings are key. I would try setting the secondary float level to be even with the bottom of the sight window and see if that makes any difference. If it doesn't you can always set it back where it was. Also, have you tried looking at Quickfuel's website (if there is one) to see if they provide any information there?
The secondaries open before you get to full throttle. That is when the secondary accelerator pump is activated. I'm almost sure the problem is in the secondary fuel enrichment circuit. If the problem corrected itself, there may have been some trash in the passages of that circuit.
Make sure to get your float level issue addressed.---Chuck
Hey guys thanks for the info,today i adjusted the pump cam secondaires counterclickwise just to see if that helped, it dropped the idle alot so i adjuted the idle screw and brought it up to about 900.I then tested the Wot and it performed alot better and seemed alot smoother,no bog or hesitation, the throttle response seems smoother and more crisp.Did i correct my problem for good? The primary float level is where it should be (the fuel sits at the bottom of the sight glass) The secondaries still have the fuel about 3/4 of the way to the top.You guys think i should take that float level down also to match my primaries? If doing so will that affect anything? Thanks again guys, youve been a real help!
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1987 Mustang Gt,Primer Black: 4 inch Ram Air Hood,351W bored 0.30 over,Holley 750 double pumper with 50cc accelerator pumps,Edelbrock victor jr intake port matched to Dart cylinder heads,Crane cam 630 lift,Accel ignition,msd coil,Msd 6AL box,Underdrive Pullies,Bbk long tube Headers,Flowmasters with dumps,Zex wet kit 125 shot,Full set of Autometer Gauges:Fuel level,Water temp,Volts,Oil,Air/Fuel,Vacumn/Boost, Subframe Connectors,Aluminum Driveshaft,Rollcage,Weld Draglites 5.5 Fronts 10.5 Rears
Are the idle mixture screws only suppose to be 1 1/2 turns out on either side for "most" setups? And you're suppose to see fuel on the bottom of the sight glass on the primary AND the secondary bowls???
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1989 GT - DSS 331 short block, Eibach Sport line springs, Magnaflow CBE, Pypes Headers/mid pipe, Trick Flow Twisted Wedge Heads & 1.6 rockers, Cobra upper/lower, 24 lb inj......so on and so on...
Help Tuning My carb for my 351w 
