There's your answer.

Is it wise to run an external filter? Absolutely. I run a filter in my gas can, so the gas is filtered before it ever leaves the can and heads towards my plane. I run felt clunks, so there's a filter in the tank. And I run a filter in-line between the tank and the carb.

I always run a 3-line tank, so I never force fuel BACKWARDS through my felt clunk to fill. I fill through the 3rd line. Fuel gets filtered before it leaves the can and goes straight into the tank via the fill line. It then gets filtered by the felt clunk on the way out of the tank. And it passes through the external in-line filter before it enters the carb.

I've never taken a carb a-part and found so much as a SPEK of crud in one of the screens. Gosh, I wonder why?