Mercury - Quicksilver 823534 Fuel Filter Fits Most Portable Fuel Tanks 823534. Overview. Clean fuel is the key to a smooth-running outboard. The Mercury 823534 Fuel Filter keeps dirt and debris out of your fuel system, protecting your engine from performance loss or damage. Designed to fit most portable fuel tanks, this OEM filter uses a fine 150-micron screen that traps harmful particulates before they reach your motor.. It's a quick, affordable safeguard that helps your engine start easier, id