I have done a search, and it seems that most all rochester threads have to do with tri-power. My problem is that I have a pair of dueces on a vintage speed intake! I have #52 jets, running progressive at a 60-0 split. I have completely gone through them but it still runs too rich. I have a low pressure electric pump, a mildly built small block with a two speed power glide. I can get the car to idle fine, but when I put it in gear, it just dies. If I turn the idle mixture screws, the ones on the left they make a difference, but the ones on the right do nothing! I have tried to disconnect the vac*** lines, and the car runs a little smoother in park, but it still dies when put in gear. Any ideas? I am really getting frustrated, and am about to go with a.... well I won't say it!
Im no guru by any means, but Ill take a stab at it. Im ***uming your plugs are fuel fouling and thats why you are thinking its running rich correct? You have read the plugs? Im thinking your having more of timing issue than a carb issue. Also check for vacuum leaks around your adapter.
I am at 12 degrees the fuel pressure is at 3.5 and I have checked the floats twice, but I may need to check them again. I just used the cardboard guide that came in the rebuild to set them though, any better way to set them? I will say that I can not see any other fuel running or dripping in the carbs.
First off, float level won't effect one side of a carb (except Carter/ Edlebrock) and not the other. I understand from your description that the left and rt screws on both carbs act the same, but different from left to right. This is not a timing problem. It is mechanical. either the same thing is wrong with both carbs(not likly) or a problem is wrong with the manifold or internal in the engine. If you have an intake that the left side feeds the left bank of the engine and the rt side feeds the rt bank, then look to the bank that doesn't react to the mixture. Most intakes are 180 degree -one side of carb feeds two cylinders on one bank and two on opposite. Probably with either type, you have a vacuum leak - either a gasket failure or port alignment if this has been going on since the intake was installed or the engine was built.
I would agree with wildethang that your issue is probably not carburetion. Generally, a vacuum leak will cause a lean condition, not rich. Two issues which might cause the idle issue you describe and the rich condition are: (1) Low compression on 1 or more cylinders (2) Poor ignition (an electronic conversion giving problems on one or more cylinders). If it should be carburetion, running a progressive linkage and two carburetors which are too small can also cause the symptoms described. Dual deuces with progressive linkage is DIFFICULT! Everything needs to be perfect, and then it still won't perform as well as solid linkage. Jon.
Carbking; I have a fresh built motor, with great compression, and am running a regular dist. with vac*** advance. I was told to run the carbs progressive, but this has proven to be a *****!!! If I change the base plate on the secondary, back to a regular plate not cammed, should I go back to #56 jets? I have not checked for a vac*** leak at the base adapter, but the car runs at higher rpms without the trans vac*** attached, or the dist. vac*** attached, then it will also eventually die. Thank you for your replies, I need all the help I can get with this setup, or else the notorious Edelbrock 1406 is going on. I had no problems breaking the motor in with it, and that is why I am so frustrated. I have pulled the carbs on and off about 6 times, rebuilt them, change the jets, gaskets, and ect. I really like the look, but is it worth the h***le? I don't know!
Okay, you know it ran properly once. Is the only thing you have done is add that adapter to put twin carbs on a single four barrel intake? If so, you know it has to be there. Now, surely someone close by has a 4-bbl to single 2-bbl adapter. Borrow it and put one carb at a time on. If each runs ok, then you know it has to be the adapter or gskts. If not, repair or tune each carb individually and then reinstall, double check where the adapter mates to the intake, because there many different opening designs on chevys. And truly progressive linkage like this is not to good. I don't understand why you would want twin carbs on a single carb manifold. The amount of work to get them satisfactory is substantal and performance goes down, not up. For looks, get a 3-2 and block off the end carbs. hope this helps.
Oh yea, I forgot, jets have practically no effect on idle. Get you a good book, the one on rochester quadrajets is super and it has some on the 2 bbl, and look at the theory section. It is simple enough to understand that you don't need ten years of physics.
I wanted to be a little different, since it is a chevy and all. I am just having a hell of a time with what is supposed to be SO easy to bolt on. If I could find a decent priced tri set-up, I would probably go with it, but good grief people think they are gold. It is a driver, and if I can't get it dialed in right, the four will go back on it. Thank you for your input.
OK - more information please: (A) You started the engine and did initial break-in with a four barrel? If so, that would tend to eliminate compression issues. (B) You have "points and condenser" distributor, which tends to eliminate the single cylinder electrical issues. So questions: Is the intake system a real intake manifold; or is this one of those double two barrel to four barrel adapters? If a real manifold, did you change intake gaskets when you removed the four barrel manifold? And have you performed a gas test for gasket leaks? If you are using one of the double two barrel to four barrel adapters; then I have no more questions, and no answers; other than call the vendor who sold you the item with the promise it was so easy to bolt on. Jon.
I had a problem like that, I cured it by opening up the idle tubes .002 at a time until it would idle "good" in gear. Thats was quadrajet, but the same should apply to 2g. I agree with the above post, check for vac leaks first.
Did the same on my 2G's tripower set up atop a blower, I actually found that at one point I drilled too much, I filled the holes back in with JB weld and put it back were I needed it. I love the 2g's, very easy to work with, once you have the tubes were you need them then you can worry about the jets.
Carbking: yes it is one of those two to four adapters. Thank you guys for all your input, I will try the drilling of the idle tubes.
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