It's as common for guys to ham-hand the fuel filter fitting as it is for them to ham-hand the oil drain plug, with the same result- stripped threads. They take nowhere near the tightening some guys feel is necessary to avoid leaks. Take a careful look at the thread in the casting to see if there are enough there for a good grip. There's a gasket that keeps it from leaking; the threads don't do the sealing...unless someone ham-handed it. Best solution I've found for that (instead of buying another carburetor, since I was po) was to J-B Weld the fitting into the carb body and put on an inline filter (leaving out the internal filter, of course, but I've seen them left in when trouble shooting).
If you end up doing that, only buy a metal filter. The glass and plastic ones are famous in a way that you won't enjoy, if they leak.
