Triumph Repair: spitfire sneezes, hydraulic resistance, jet adjustment

Question
QUESTION: I was wondering how to adjust the air and fuel mixture.  When I step on the gas
while in gear the carb sneezes,  otherwise it sounds great at idle.  I know my
timing is right and the engine and carb have just been rebuilt.  Someone told me
that it may be running either too lean or too rich.   So how might I be able to
adjust this?   Thanks a lot, any help would be great.

ANSWER: Jason, it depends on what Spitfire you have. One with twin SUs or one Stromberg carb.

---------- FOLLOW-UP ----------

QUESTION: its a spit MK IV with one stromberg carb

Answer
Before you condemn the fuel mixture for a "sneeze" back into the carb when accelerating, you need to check what takes the place of the accelerator pump on a Stromberg. Unscrew the top cap and lift the cap up about 2 in. and push it back down. If you don't feel like you are pushing on hydraulic resistance, put a few squirts of engine oil in the top and try it again. Then if you get the hydraulic resistance go road test the car to see if it fixed the problem.
If you did have hydraulic resistance at first, get a long 3mm Allen wrench and down in that top tube where the oil was is the jet adjustment. Clockwise richens the mixture. Road test between each half turn.
If that don't correct the problem, you could have other problems like a leaking intake valve, a vacuum leak, air filter not in place or even a fouled plug.
A rich mixture will not make it sneeze back on acceleration.
Let me know how you do.
Howard