ORIGINAL: Paul Cataldo
That's right gentlemen! You can't filter that fuel enough! Whoever said "there is no way debris can enter the line between the tank and carb" (when pre-filtering the fuel) is incorrect.
I swear if you have a filter between your tank and carb, it WILL eventually get dirty, regardless of having 2-3 other filters before this point. It just happens.
I said that, and it is true.
If the first filter in the carb supply line does not stop all debris as needed, that filter is no good. In my experience, felt clunk, or sintered filters are good enough. In line filters like a previous poster showed will add nothing, - edit - because the filter strainer mesh inside is quite course - end edit- .
Like bugman Elson said, cleaning the complete fuel supply line after a period of operation is a wise thing to do, because sludge sticking to surfaces on the filter and internal carb parts will reduce flow. Cleaning the filters is a daily chore is ship's fuel systems, which was my profession when young.
Yes, before a season, take out the tank and filters, and wash them in clean fuel without oil. Then you are good for the next season. (don't forget to clean the carb as well)
To repeat my setup:
Paper filter in funnel from jug to fill bottle
felt filter in my fill bottle
paper filter onboard the plane in my fill line
felt clunk filter in fuel pickup to carb
gauze strainer filter inside the carb.
That's 5 filters before the fuel gets to the carb operating parts.