Waldo,
I probably have a 40 FP manual somewhere if it is important I could scan it in at work and e-mail it to you. Otherwise there are manuals at [link=http://www.osengines.com/manuals/index.html]O.S.[/link] that have air bleed carbs in them that can't be much different. Seems like I remember something about putting a straight pin in that hole and adjusting the screw down for a starting point. I think all that screw does is keep the engine from loading up with fuel while idling. Of course I'm one of those dummies who you read about in the engine forums who can't adjust a Super Tigre carb but I can find stuff in that mess I call a shop. Ya want I should go look for that manual. I'm just on nanny duty tonight while my wife is at work so can't go anywhere (like to the field) and would just love an excuse to go to my shop!