Any advice on tuning the OEM carby on a Z24 motor... Runs fine but idles at 2000 rpm... Adjusting the idle screw back any further only causes the engine to die.... I have slackened the throttle cable back, so it is not interfering with it... The only thing I can think of is the choke isn't coming off... Any other advise would be awesome... It has been at least ten years since I have had to play with carbs...