I'm running a Quick Fuel VS580. Like it ok, but get better accelleration from the Holley Avenger 570.
Quick fuel 650 DP on the Sprint (Need a bigger Acc pump squirter on the primaries) Otherwise it works really well.(Power improved noticably according to the seat of my pants anywhoo) Very massaged Holley 600 vac secondaries on the 302 in my blue mav.
I will look into that. It came off of a 1967 Firebird with a 454. Apparently it ran great and only has about 500 miles on it, but the guy wanted a new carb that had some red anodized color on it so it would match his car.
QuikFuel 650 SS on the 347 with original jets and air bleeds and larger nozzles and more aggressive fast idle cam. Its great under WOT but idles rich when warm and not good at all till it warms up. Also put a resistor in the electric choke circuit to keep the choke on longer. Installed a 2400 stall converter to loosen it up on idle 'cause it doesn't like to idle below 850-900. All 4 idle mixture screws are set about 1/2 turn out. I wonder if it needs bigger air bleeds but I'm afraid to touch it since I've paid two pros to work on it to get it running decent. Wish I knew someone local who could get the idle and cold start better. Its hard to find anyone around here that will work on a carb and it might be impossible to find a real expert who will spend the time.
Idle screws a half turn out is likely too lean. Set your initial timing, then set the idle speed screw, then fine tune the idle with the mixture screws. With a 650 on a 347, it shouldn't even need a choke, you should be able to baby the pedal a minute ot two on the coldest mornings to get it to idle on it's own without a choke. This is all it takes to get my 331 idling after sitting a week in the garage in the dead of winter and there's no choke on any of the carbs. My converter has a lower stall speed than your 2400 and it'll idle at 500-600 rpms in gear after giving it a few minutes to warm up. Learn to tune your own carb, it's not a hard thing to do, anyone can do it. Just remember one thing: it's not EFI, so don't expect it to be dead on at all points in the rpm range (if you're using a carb that's too big for the application) and also remember that if you think the carb has gotten "out of adjustment" it's likely not the carb that's the problem, but something in the ignition system acting up. Once you set a carb, it'll stay that way for years, in all kinds of weather.
Hey Earl, Put a 10 ohm/100 watt resistor in series with the elect choke. Wish I could remember where I got it. Its a nice one with a finned aluminum case for about $10 IIRC. It approx doubled the time on the fast idle cam. Jim
I suspect its rich on idle because the exhaust smells rich and it starts to miss (loading up?) if it idles for a while in gear. But, is the exhaust rich because the lean condition is causing misfire on idle and putting unburned fuel in the exhaust? I don't know. It idles AWFUL if the idle mixture screws are out any more. That's why I wonder if it needs bigger air bleeds to match more fuel thru the idle mixture screws. As you can see, I don't have a clue on what to change in which direction. And since I spent months and paid two pros to get it to run decent, I'm reluctant to change anything without a carb expert and I haven't found one yet.
Mine is similar. Awesome under WOT, and a slight hesitation as it flips from primary to secondary circuits when the engine is cold, or when the weather is really cold. But once it warms up (engine AND weather), which is where it is tuned to, it is all ballzout! But no choke, so it can be a biatch to start in cold weather. Always smells gassy at idle...I messed with it, and when the gassy smell goes away, I also lose my idle, so I guess I need to just learn to live with it. It isn't "burn your eyes" gassy, but just a bit stinky.
I also wonder if its an atomization problem. I tried twice to get Quick Fuel to tell me if their annular boosters are available for the 650 SS. I can't tell from their online parts listing and haven't gotten an answer from Quick Fuel yet.
If you're using all four idle screws, stop and just use the primary screws, close the secondary screws. Do what I suggested before (setting the timing & idle speed)then close the primary screws, then open each one, 1-1/2 turns, then start the engine and once it's warmed up, fine tune the idle with the primary screws. You don't need a carb expert, you just need to learn the basics and do it yourself. This is not complicated, nothing to be afraid of. Whatever money you paid for that "expert" carb tuning, was clearly money wasted. I also suggest removing the choke, this may also be causing your complications. The choke is the first thing I remove (completely) from my Holleys. It's far easier to spend a few minutes babying the gas pedal to let the carb warm enough to idle on it's own than deal with a malfunctioning choke. If your ignition is hot enough and the carb isn't too big for the application and you're running a wide LSA cam, you don't need a choke period.
