Fuel Screw Well Plug Extraction

Squarely drill the plug with a 4.2 mm (or #19) drill using a depth stop so that the drill just clears the other side of the plug. The plug will be ~3.5 to 4 mm deep. You can creep up on clearing by progressively moving the stop. Not using a stop almost invariably means drilling into the screw, damaging and possibly destroying the head, as well as at minimum preventing you from determining (for educational purposes) what the original setting was, and possibly even bottoming the tapered portion of the screw hard in its seat (which may then break off when you try to unscrew it).

Thread the hole with an M5X.8 tap. Note: A 3.3 mm (or #30) drill bit and an M4X.7 tap will work as well, as would SAE sizes in the same range, such as #29 and 8-32 or 8-36, or #25 and 10-24, or #21 and 10-32. Tap only deep enough to get through the plug. Finish with a bottoming tap, as it will provide more clearance (grind off the point if it has one).

Use a metal tube or nut with an ID just larger than the OD of the plug in conjunction with a screw (matching the tapped size) and a washer with the same or larger OD than the tube/nut's ID as a puller.

A common strategy for removal is to drill a hole in the plug, screw a sheet metal screw into the hole, and then pull on the screw with a pair of locking pliers. This method has been promoted via the inclusion of a drill bit and sheet metal screw for this purpose in certain jet kits, but carries with it the risk of a broken fuel screw well.