The greatest need for the felt filter in the clunk is to dissipate the air bubbles in the tank. As mentioned in the instructions the carb is very sensitive to what most would see as 'normal' air bubbles in the fuel line. Using the included filter eliminates this problem and why we included it with the package to insure you have a successful experience. Unless you only have access to really crappy gas and if take reasonable care to keep you fuel clean I don't think you will ever have an issue with a clogged filter in the tank.

Pete