My fuel is filtered three times before it reaches the carb. One felt filter in my gas jug pick-up, a paper element filter in the fill line from my manual hand pump, and an in-tank felt filtered clunk on the carb's feed.

Early on I used an inferior quality felt filtered clunk in the tank and paid the penalty of having some of it's fibers clog the carb's screen. Since then I do take an occassional look see but since switching to using a premium quality felt filter the screen has remained quite clean.

Karol