The early one's had a rich mid range when the top and bottom were adjusted correctly. First you need to get the top and bottom adjusted right and then see about the transition through mid throttle. We need a better description than it's running like a bag of spanners....


Basic adjustment is the open the high speed needle about one and three quarters turns and start and hover it. Will it hover? what it the head temp after hovering? Should be 200-220deg F. Is there smoke? What fuel?if it hovers and the temp is good but the idle is off start the motor and get it idling. Hold the head so the blades don'e turn. Pinch the fuel line. It should run normal for 5 seconds before reving and then dieing. Try all this and post what you have...