I just bought a YS 63 from a buddy who had it for a couple of years and never ran it. I mount the thing sidways on a profile and get it fired up and then the problems start. The top end is great plenty of power running a 13x4 APC and Byron 20% Oil with 15%nitro. The problem occurs when I drop it down to idle. The idle is incosistant. I get it adjusted where it is running smooth with good throttle response and then halfway through the tank and the idle will drop and eventually quit. I have spent everyday for 2 weeks messing with this thing playing with the idle screw and moving the reg screw slightly in both directions. I haven't moved the reg screw more then a 1/8 of an inch because i don't want to loose the original setting, i have been told not to move it more than and 1/8th. Any advise would be appreciated.