I have replaced several stripped carb screws. Usually they are metric and I end up replacing them with the next larger size of standard, 4-40 or 6-32 so I don't have to make the hole too much bigger. You can get a tap and screw at hobby shop or hardware store for around $5.00 or less. take the carb off the engine so you don't get shavings in crankcase. not sure if locktite will handle heat but a lock washer will