More on the idle circuit. Carter did not cast any ports in the carb body. So if they needed fuel to get from one place to the other, a bored hole was needed. The W-1 has a lot of passage ways, thats why there are so many copper plugs everywhere. The idle circuit has a lot of openings, you cannot just blow out the whole system with air, you can't get to all the holes with your fingers to direct the air where you need it to go.
Do you have a copy of the service procedure?
http://www.thecarburetorshop.com/Carter_W1_service.pdfLook at picture 8 and 9. In 8 the idle adjusting screw is being pulled out. You see the casting of the body right above the screw that is straight up and down? That is the down leg of the fuel path. At the top of that casting tube, you can see what looks like three dimples. The right side dimple is the port where air is mixed with fuel via the throttle bore, the idle jet is directly under this and is pointing straight up at that copper plug. The middle dimple is about were the small orifice is. The left dimple is the copper plug coming from the side, this is the one you need to remove. The bore is pretty small so use a small drill bit to get the copper out. I used a drywall screw to catch the orifice and pull it out. It was fairly long so what little damage the screw did, I was able to repair it and reuse it. A good spray cleaner with a straw, might blow out the hole, try it first. You might also try to block the down leg so all your air pressure is forced through the orifice hole.
Joe
