I could not leave well enough alone... ou: I have been reading this section for some time now and cant seem to find quite the same issue, if I missed a post that explains exactly what I should do.. please forgive me. My motor is a fresh rebuild, 350, +0.30, 10:1, cnc machine bowl work, TA 294-94H cam (.474"-226'/.480"-235',110') TA intake, HEI, timing set at 36* but cant remember what RPM it is all in at Had a edelbrock 1407 (750 cfm no choke) and it ran VERY well, but I had to try the Q-jet out. I re-aquired my original carb (7042244) and got to work. Ordered Cliffs book and read it a few dozen times, bought a box of parts from quadrajetparts.com and gave it the college try. Soaked all the parts in solvent for 48 hours, cleaned with brake clean before paint, used some mig welding wire to ensure all lines and fuel passages were free of debris, and reassembled. The carb will not idle for more then 3 seconds before shutting off, once or twice giving a "poof" through the top of the carb. I can keep it vehicle running (roughly) if I give the throttle a bump every time it seems like it wants to die. My accelorator pump is a new unit from quadrajetparts and it squirts one heck of a line of fuel. The fuel pump is also from Greg and I verified its function by cranking the line into a container. It burps out fuel nicely. What I have tried/done: During the rebuild I left the factory jets and rods, figured I could get the poor thing running and go from there. Did not take out the idle tubes, but did check thourougly for debris and restrictions. Used a "silver" spring for the power piston since I usually only got 14 inches of vacumme at 750 rpm idle. Below is the spring chart.. http://quadrajetparts.com/rochester...ing-assortment-color-coded-springs-p-210.html New choke pull offs, verified that they function and do not leak Pluggled every vacuume line not in use Started the idle screws 2 turns out, didnt work.. all the way in, no change... 4 turns out, no change. Float is set at 1/4 inch below the top of the bowl. checked the needle seat with a vacuume pump.. all is well Epoxied the plugs on the bottom, I have noticed most do not like this option but the 3 times I have removed the carb to try again I have not noticed any fuel leaks. New 4 hole gasket each time.. I think I am out of info to share, or tired of typing. Sorry it is quite long but I wanted to add everything I could. Thanks to all who read this or can help..
Turn your mixture screws all the way in and see if it makes a difference. if not bump your initial timing up and lower the idle. maybe your getting nozzle drip and its floodin at idle because its not running on the idle circuit
Do you have any pictures of your Q-Jet? It may help to visually verify all the links/vacuum hoses are correctly set up. I had idling issues on my car, and determined I had a fuel supply problem. No fuel getting to the carb. Had to re-do the whole mess from the tank on up.
Back from the garage: Did not try the timing yet, but I screwed the mixture screws all the way in, 2 full pumps of the throttle and keyed the ignition.. raced to 1500 RPM and shut right off even with me feathering the throttle. But I did manage to set off the neighbors car alarm! I hope it is not the fuel issue, I did test the pump and it fills half a bottle rather quick. One thing I must admit, I did not attach any linkage to the rear pulloff as you will see in the pictures. I took the choke flap off as well. It is pretty warm in the garage, so i ASSUME its not that big a deal? I really just want to see this thing run on its own steam so I have an idea where to tune.. :ball:
And!!! I guess it just must be that time... but I found 2 new puddles of coolant leaking :af: :af: :af: :af: :af: :af: Buick is probly mad at me for taking it apart, AGAIN
Now Is A Good Time To Check Throttle Position. With The Carb Removed And Drained. Look At The Primary Throttle Blades From The Bottom Of The Carb With Linkage Against The Idle Stop Screw. The Throttle Blades Should Only Be Exposing The Transfer (vertical) Slot Approx. .020". If The Transfer Slot Is Exposed A Lot Or Fully. You'll Have To Go Back And Address The Idle Circuit. Check For Correct Air Bleed Size And Pull The Idle Tubes And Replace With Correct Size Ones, Measure Idle Down Channel, Check All Surfaces For Flatness. Call Cliff With Your Findings, He's Great At Steering You In The Right Direction. Good Luck
No adapter, it bolted to the TA intake pretty well I thought, but then again o No: That is one thing I am unfamiliar with, but after reading your post a few times and reffering to "the book" I understand what you are saying. To be perfectly honest I hope it is something simple I am missing, but if I need to take it off for what ever reason I will check. On another note, is there a way to check hole sizes (air holes, idle tubes ect..) without buying a bunch of drill bits?
hmm. i would think on a square bore intake the throttle blades would hit. Could be wrong though. On a quadrajet the primaries are way forward compared to square bore. maybe 1.2 inch or so
True indeed, but my (not sure of everyone else's) TA intake accepts a spreadbore. I do have full range of motion with the throttle blades. And on that note, I did Cliffs modification to ensure my secondary plates opened to and stopped at 90* Thanks for the help Lonnie :TU:
Got anyone to sit in the drivers seat to keep it running while you mess with it. have i suggested manifold vacuum on distributor yet? get it to idle Up a little
I suppose I could grab someone, I have managed to start it from a open window and then sprint around to the motor to fiddle with it to keep the motor running. But I do not run a vacuume advance so I plugged all ports on the carb. with the edelbrock the motor ran well without the advance. I did notice though that the throttle seemed "on edge" all of the time. It is hard to describe but while driving with the eddy it was like I was always in a lower gear then what I was in although the RPMs proved otherwise. I could cruise but it always seemed like the motor wanted to jump from its own block while maintaning speed. Not overreving, just excited...
i would run the carb screws where you had them to start Hook manifold vacuum to the distributor and start it. after about a minute of running see if it will idle. the puff of smoke suggests flooding.
Biggest problem, trying to use an emission calibrated carburetor WAY outside of what it was originally set-up for. Second problem, that's a pretty "hefty" camshaft for a 350 engine. Over 290 degrees advertised duration and 110LSA....nearly as big as what I use in my 455 with 11 to 1 compression. Not pulling the idle tubes, and setting the carburetors idle system up exactly for the application is why you are having problems. I'd also make sure there are no vacuum leaks, as it just makes things worse. Take the carburetor back apart, set it up according to the 3rd "recipe" in my book, and try it again. That much camshaft in a 350 engine requires a LOT more idle fuel than the 244 carburetor was designed to deliver. It may need a tad more fuel from the main system, and a lighter PP springs as well, but first I'd get the idle fuel problem corrected, then tune the rest of the carb if/as needed.......Cliff
Have you tried that 7043240 carb that you bought from me? I had that on a `70 RAIV Pontiac with a .516/.516 230/240 cam and it idled great.
Hey Bill! I did try the carb I bought from you but it did not take, I am guessing it is because I threw a 800cfm carb straight on the 350 before modifying anything internally? I did not know anything about Q-Jets before ordering yours, but since I started this carb quest I have been learning more and more.
I did, capped off the PCV and the inlet to the carb. Didnt have the right size tubing floating around at the time. Pardon my inexperience, but will not having a PCV hooked up effect the carb that much?
