Have a single 48 powerbomb on a 701 SJ, b-pipe, and pump gas head. It appears to be "leaning out" at full throttle after a few seconds. With the ski on the trailer and the hood off, the engine will pull and hold peak RPM for a few seconds, then die as if it is out of fuel. The fuel in the lines and filter appears to be OK (plenty of volume). If the throttle is backed off to 3/4, fuel is pulled out of the venturi and the engine runs fine..........once wide open, the fuel stop being pulled from the atomizer, almost as there is not enough signal at WOT. Fuel always returns when slightly closing the throttle. Needle settings have no effect.

Are you running a Fuel Line Return Restrictor?



This should resolve your problem easily. Start out with a 60 main jet. Install it just before the fuel tank in the return line.