Hi Guys,
 
So I've got a 38/38 carby that looks like it is very good condition. Its not old and dry, its nice and clean and has been looked after.
 
The jetting in it is as follows.
 
Main Jets: 145
Air Correction Jets: 170
Idle Jets: 45
Pump Jets: 70
Emulsion Tubes: F50
 
Then engine is totally stock, and has just been rebuilt. It has good, even compression on all cylinders.
 
So the problem I have is, when the car is cold (even with the chokes inactive), and I put my foot to the floor from idle (not driving, just parked in the garage), it revs up nicely. However once the car gets warm, and I try to stamp my foot on the throttle, it will sound like its bogging down for about 1 second (IE: wont rev up) and will then get going.
 
I bolted this carby on, and it seemed to smell like it was running very rich, so I must admit I did have a bit of a play with the idle mixture screws (the ones on each side at the base of the carby). Wether this problem reared its head as a result of that, or wether I just didn't notice it until I played with the screws im not really able to pinpoint.
 
What I do know is Ive tried everything to try and get it revving up smoothly, but just cant seem to get it working properly. I tried following the guidelines from this website http://www.redlineweber.com/html/Tech/38_dgas_tunning.htm, but it seems to make no difference at all. The only thing I notice it that the idle changes (read mixture) as I play with the adjustment screws.
 
I have checked everything for vacuum leaks, and am quite sure there are none. All of the hoses are new, and have been double checked. I have sprayed RP7 around the manifold etc with no change in behavior on idle, so I assume everything is OK on the leak front.
 
Can anyone lend any suggestions as to what might be going on?. Ill admit im not a carby affionado at all, in fact im probably more dangerous than effective!!, so I may have missed something here, but I would have thought with all the combinations of stuff ive tried, something should have either improved or worsened the behavior.
 
Thanks to anyone for any assistance.
 
Dave

A quick google came up with this
http://www.rsownersclub.co.uk/rsocbb/showthread.php?t=74679
 
 
try a 185 air correction jet and 60 pump
 
Or a rolling road session if you don't mind parting with the $$$ :)
 
Idle mixture screw should be 1.5 turns out from all the way in, as a starting point.
 
 

What was the compression?
What is your ignition timing?

If its only when you stomp on it, then go the smaller pumps as per above. Without a choke and ok when its cold would indicate too rich imho. I believe the air correction jet is used to fine tune the top end mixture

From my understanding the emulsions "shape" the fuel cure and the air corrector sets the volume/amount of air introduced thru the emulsion. A secondary effect is it also sets the "timing" of the main circuit, larger weakens the signal causing a delay.