The use of a "Felt clunk" is essential to reliable engine performance, especially with Petrol Motors and Jets, but also Glow engines.

They have several properties that make them very attractive.
The "Felt" acts as a very effective fuel filter.
The "Felt" holds fuel causing a small pool that insures a constant fuel supply to the carb under all conditions.
For instance, on a 'down line' when the clunk isn't fully in the fuel or when the tank is not full, the fuel splashes around and is collected on the felt thus avoiding air bubbles entering into the carburettor, eliminating those annoying blups of power!

Most times it will drain the fuel down to the last drip!

Can be used on Petrol, Diesel and Glow.