Can anyone provide direction with regard to setting the air/fuel mixture screw to either A) the factory intended setting, or B) the setting appropriate for an '84 Euro 500 SEC. The screw has been tampered with and the result is has been an idle that several minutes after startup "lopes" or "hunts". The throttle plate is pulsing at this point as if it is gasping for air and is rhythmically opening and shutting. How do I restore some constancy to this plates erratic and miscreant behavior? If I can reset the mixture myself what other tools/equipment in addition to a long stemmed 3mm Allen wrench will be required? Thank you in advance for your replies. William Canon.