Keep the heart of your Verado or MerCruiser running smooth with Mercury’s Fuel Castle Filter 35-8M0122424. This is the factory cartridge that snaps into the “castle” bowl on every L4 Verado, 200-300 HP L6 Verado, and the new-generation 4.5 L and 6.2 L sterndrives. One quick twist, a snug O-ring seal, and your high-pressure system is protected from the varnish, water, and grit that sideline injectors.

Why the genuine filter earns a place in your 100-hour service kit

• Tight 10-micron pleated media traps fine debris without starving the pump at wide-open throttle.

• Reinforced nylon end caps handle 90 psi fuel pressure and hot-soak temps up to 220 °F.

• Keyed castle tabs align instantly—no cross-thread drama or special tools needed.

• Nitrile sealing ring shrugs off ethanol blends and keeps air out of the rail for fast, fumeless starts.

Swap it during every annual or 100-hour service: relieve pressure, pop the bowl, drop in the cartridge, prime, and go. You’ll notice quicker cold starts, steadier mid-range pull, and the confidence that every gallon of 87 octane reaches the injectors clean and water-free—exactly how Mercury engineered it.