Sierra Fuel Filter 18-7846 — Medium 21-Micron In-Line Marine Filter with 1"-12 Thread

Sierra International 18-7846 is a medium-duty in-line fuel filter rated at 21 microns with a 1"-12 threaded connection, designed to replace OMC, Crusader and Volvo OEM filters.

This compact replacement fuel filter is built for marine and recreational engine applications where reliable fuel cleanliness and straightforward installation matter. It fits common OEM part numbers including OMC 502905/174144, Crusader 98041, and Volvo 3851218-2, offering a universal-fit option for technicians and boat owners looking to restore proper filtration without changing mounting hardware.

How does this filter protect my engine against contaminants?

The 21-micron rating captures medium-sized particles that can damage carburetors, injectors, and fuel pumps while still allowing good fuel flow. By trapping debris, rust, and precipitates, it reduces wear and helps maintain consistent fuel delivery.

• Captures particles down to 21 microns for balanced protection and flow
• Media designed for common gasoline and light diesel marine fuels
• Reduces risk of injector clogging and pump abrasion

Will this fit my engine and how easy is it to install?

The Sierra 18-7846 uses a 1"-12 threaded connection and is listed as a universal fit for several OEM references, so it bolts into many original filter housings without adapters. Installation is typically a straight swap: remove the old filter, check seals, and screw in the replacement.

• Thread pitch: 1"-12 to match OEM fittings
• Direct replacements for OMC 502905, OMC 174144 and Crusader 98041
• Recommended: inspect or replace sealing gasket during installation

What are the material and warranty details I should know?

Sierra designs this filter for durability in marine environments with filtration media and construction suited to fuel exposure. All Sierra parts carry the company's customer satisfaction warranty, giving you coverage if the part fails under normal use.

• Rated 21 micron for consistent particle capture
• Constructed for fuel compatibility and marine conditions
• Covered by Sierra’s industry-leading customer satisfaction warranty

How do I choose replacement intervals and maintenance tips?

Replacement frequency depends on engine hours, fuel quality, and operating conditions; inspect the filter at routine service intervals and replace if contamination or flow restriction appears. Keeping fuel tanks and lines clean reduces stress on the filter and the fuel system.

• Check filter during each seasonal service or every 100 operating hours
• Replace sooner if you notice decreased performance or visible contamination
• Drain water separators and use recommended fuel stabilizers to extend life

Who is this for: The Sierra International 18-7846 medium fuel filter is intended for boat owners, marine mechanics and small engine technicians who need a dependable OEM-compatible replacement. It suits applications that specify OMC 502905/174144, Crusader 98041, or Volvo 3851218-2, and for anyone seeking a 21-micron, 1"-12 threaded solution that balances particle removal with fuel flow. Choose this filter when you want a direct-fit replacement backed by Sierra’s warranty and built for routine marine service tasks.