Groach2588
New member
I have a 1968 20hp that I've started using after being stored for a few years. It started, idled and ran pretty well but just didn't seem to open to full rpm. Also tended to die at idle. Did notice that butterfly wasn't completley horizontal at full throttle. An acquaintance suggested spraying Sierra Carbon Free in while running. Did then open up to full rpm. Adjusted needle valve for amazingly nice slow putt putt. But now it doesn't open up to full throttle again and high rpm bounces from half power to 3/4 at full throttle. Was suggested that high idle jet has blockage and that I need to dismantle carb and clean high jet. Does this seem accurate, or is there another possible explanation?