I have re-jetted it from the stock 145 to a 150 and it ran great re-did the intake set up got rid of the box and it started cutting out at 3/4 to WOT I jetted it up to a 155 and it got better but it still does it just further past the 3/4 range of throttle. So I don't think it is rich, plus plug is new so I have ran it at idle to see how it is running on the low cycle of the carb and it is nice brown paper bag color, took it out ran awesome as long as i stayed away from WOT. I am currently set at a 155 main, 3rd notch on the needle, 3 turns out on the mixture screw. Could it possible be lean on the top end? Its not bogging down like it is too rich just cuts out?