This video is on Accelerator Pump shooters or discharge nozzles, and accelerator pump cam tuning. This is a difficult video to make, as a step wise direction format. You really have to look at the overall process, and adjust all components involved. This includes the pump shot, accelerator pump cam, and accelerator pump spring. One of the main things to take from this video is to identify the stumble or hesitation, and correlate it to the position of the throttle. This position can tell you if you need bigger shooter/discharge nozzles, if the issue happens, it occurs as soon as you put the throttle to the the boards. This is usually fixed by increasing the pump shooter size, but you also have to evaluate the Pump cam, and make sure it is not running out of fuel. The volume of the accelerator pump is either 30 or 50cc, that is the total volume you have to work with. So you either have to increase pump shooter size, and or change the duration of the pump shot, this is done by changing the pump cams. It takes some diagnosis, to where in the throttle position the stumble or hesitation occurs, then adjustment time. Try increasing pump shooter size, if it gets better, then great, then think changing the accelerator pump cam, to tailor the length of the pump shot. If that help again, great job. If it does not help, then you have to better evaluate the stumble or hesitation, in relation to throttle position. Anytime you change the pump shooter and especially the cam, MAKE SURE YOU CHECK THE ACCERATOR PUMP OVERIDE SPRING, and adjust accordingly. As John mentioned, when you get a stumble while on the two step, trans brake, then there other things to consider, float level,