[Austria_Cobra]

Hello
Actually I am beginning to adjust my QFT on my Cobra. I would like to ask you a view things, to improve my knowledge of carburetors work.

351W stroked to 427cui
650QFT (I know it is a bit to small)
MSD Ignition 83541 Ready-to-Run, Coil Blaster, Ford Racing spark wires, Champion RC12YC, limiter to 5.500rpm

Basic setup on QFT 650 HR mechanical sec. (E-choke)
- primary throttle plates on square of transfer slot
- secondary throttle plates nearly closed
- primary main jet 72, secondary main jet 82
- idle air bleeds 70, main air bleeds 28
- idle restriction jet 28
- idle mixture screws at 1.5 turn
- idle speed screw 1/4 turn to square transfer slot
- fuel level at half of glas at 6.5psi (electric Fuel Pump with regulator)

startup of engine. worm up.
-> to get to an idle(850-900rpm) with the most inHg(10) on main manifold, the idle mixture screws ar at 0.5 turns, 18° ignition, idle speed screw at 0.5 turn.

test drive
-> on thrust load and part load the engine starts shaking, is not running smooth. Feels like one cylinder does not have an ignition. idle mixture screws to 0.6 turns made it quite better, but still not fine.
-> after pushing the gas pedal 2mm the engine runs great until limiter with much power

OK, this is the situation right now.

First thing I would like to know is, what are the steps to do, to get out the idle mixture screws to 1.5 turns (is there a difference on small adjustments with 0.5 turn and 1.5 turns ?), or should I leave it as it is.

I just got an AFR gauge and this will be the next step for me to find out if the engine leans or richens on thrust load and part load. (should lean)

The next thing will be adjusting idle and part load. Therefore I have to adjust the idle air bleeds and restriction jets.
My actual thinking about that is, that I have to adjust that for part load. Because the mixture is coming out of transfer slot and no other adjustment can be done. The idle mixture screws have to be adjusted after, to get back to a good idle. I am correct ?
This will also take affect that my idle speed screw can go back to 1/4 turn, correct ?
I think of a lean mixture, that needs to richen up (air bleed smaller, restrictor bigger), means also that my idle mixture screw has to go in, but I am at 0.5 turns...?
Because of this fix situation to transfer slot, I do not see a way to get the idle mixture screws to 1.5 turn out, wrong?

Thx
Richard