Thinking further . . .
Are your accelerator pumps giving a little shot when the throttle advances from idle? You should be able to see it when you look down intro the throttle bores from above. It should be an even, fine mist.
2005 X2, Viper Red, MCX, OJ TZ-X5 prop, PPass, rear 750 sacs, KGB, IBS, Bennett Wake Plate, custom wake shaper
(previous) 2001 X5, 1991 TriStar 190