these are close to 40 years old.there were two types of r/c carbs one that had the needlevalve/spray bar as part of the carb the other had the needlevalve/spray below the carb body and it retained the carb to the engine,this was the earlier version.the later version was just a standard airbleed type carb and it is set like todays airbleed carbs.sorry I have no manual