I have a side question about low speed tuning... The manual of my mach .15 engine states the low-speed needle turning should be done with the carb fully closed.. Would this mean backing out the idle screw any time you wanted to adjust the low speed needle in order to get the carb fully closed ?? I picked up a truck used, and want to set needles back to the recommended break in settings since i do not know what they are set at now, but this note about the low speed setting has me a little confused..