RE: B&S 40cc, 4-stroke recipe for success
Next, you need to tap the holes for the pulse line fittings in the engine manifold flange and the carb fuel pump plate. Here are some pics that show what it looks like when done. It has been suggested that a spring should be used inside the pump which I tried but decided to leave out for now since I wasn't able to get it to work right and so far the engine has run fine without it.