Since I use all four strokes nowadays most of my engines [os4st's]have a hole in the needle valve with a set screw for an extention. it is a litle small for 2-56 so I drill it out to take a 2-56 and put a short[1/4 - 3/8]2-56 socket head screw in it held in with the set screw. Then with the cowl in plsce with a 1/8th hole you can run a ball driver straight in and find the screw pretty easlily. Thus you only have a tiny [1/8] hole in the cowl.