tuning
turnig your needle screws clockwise leans out the fuel not the air. when you turn them clockwise the needles are going farther into the hole thus restricting airflow more. if you two are having the stall problems like you describe first make sure your motor is up to temp first. then adjust your idle leave it kinda high, not like you would set idle on a dirt bike, it would be a little higher than that. if you still have stall problems makes your lines are not cut in anyway and that the oring on your tank is not damaged. air leaks in these areas will cause stalling.
good luck,
also traxxas has a dvd that really explains tuning very well and it comes with the revo, maybe someone at your track could let you borrow it, of see if traxxas sells them seperate