i dont know if you have a droop or not???, but sometimes those can cause a problem with getting water into the bowl when you first launch...
i would just install a burp valve on your bowl, and it should take care of the problem completely. its what most drag racers use now because of the same problems they were having... just call a local pump builder and they should have one in stock, i think they're about 55 +/-... if you dont have anyone to call, then call jim at 818-890-1867, he has them