The Sierra International 18-7844 fuel filter is presented as a compact, 21‑micron inline unit rated for about 90 GPH, suitable for many marine and small-engine applications. It fits common Mercury equivalents, traps particulates and moisture, and handles ethanol blends; installation is usually straightforward. Key points: compatibility with Mercury 35‑807172, 21 µm rating, 90 gallons per hour flow. Questions: How long will it last in ethanol fuel? What warranty covers defects?
Key Takeaways
- Compact replacement filter (3.875″ length, thread pitch 42690) offering straightforward fitment for compatible fuel systems.
- 21-micron rating with 90 GPH flow balances particle removal and adequate fuel delivery for moderate-duty marine use.
- Effective with ethanol-blended fuels, trapping particulates and moisture for improved engine protection.
- Replaces Mercury 35-807172 and 35-802893Q; customers report reliable fit, flow, and real-world performance.
- Seasonal-to-annual service life depends on fuel quality; verify thread compatibility and mounting clearance before purchase.
Product Specifications and Compatibility
A compact replacement filter, the Sierra International 18-7844 is designed for straightforward fitment and reliable fuel filtration. It measures 3.875 inches (98.4 mm) in length, features a 42690 thread pitch, and weighs 0.09 ounces.
What are its key specs? Micron rating: 21 microns; flow rate: 90 GPH; material: plastic.
Which vehicles fit? It replaces Mercury 35-807172 and 35-802893Q and offers universal fit type for many applications.
Considerations: product dimensions, thread compatibility, and mounting space.
How effective is it? Filtration efficiency balances particulate capture with acceptable flow, suitable for typical marine and automotive uses.
Performance and Real-World Use
When evaluating real-world performance, the Sierra International 18-7844 demonstrates dependable filtration for moderate-duty marine and automotive applications, balancing a 21-micron rating with a 90 GPH flow rate to protect fuel systems without overly restricting supply.
It performs well with ethanol-blended fuels, trapping particulates and moisture-laden debris.
Installation tips: orient filter correctly, hand-tighten to specified thread pitch, and prime fuel lines after replacement.
Q: How long does it last?
A: Lifespan varies by fuel quality and hours, typically seasonal to annual service.
Customer feedback rates reliability high, praising fit, flow, and simple replacement.
Availability, Pricing, and Warranty
Following reliable on-vehicle performance and routine service guidance, availability, pricing, and warranty information help determine whether the Sierra International 18-7844 is a practical long-term choice.
The part is widely available online, ASIN B0001CLG2S, first listed June 8, 2005; retailers often stock the short 3.875″ (98.4 mm) unit, thread pitch 42690.
How much does it cost? Prices vary; report lower prices with URL, shipping, date for adjustments.
What about returns and warranty? Amazon’s voluntary 30-day return applies; manufacturer warranty details are limited.
Check customer reviews and product comparisons before purchase.
Frequently Asked Questions
Does It Come With Installation Instructions or Mounting Hardware?
Like a simple map, the product lacks included installation instructions or mounting hardware. Reviewers note installation ease depends on prior experience; hardware quality cannot be assessed because buyers must supply fittings separately.
Is the Filter Reusable or Serviceable?
No, the filter is not reusable; it is a disposable replacement. The detached observer notes filter maintenance requires replacing the unit at service intervals, though reusable options exist elsewhere for those seeking rebuildable or washable designs.
What Is the Expected Service Interval or Mileage Recommendation?
A general service interval recommendation is to replace the fuel filter every 1–2 years or 10,000–30,000 miles; mileage recommendation varies by fuel quality and usage, so more frequent changes suit high-horsepower or ethanol-blended applications.
Is It Safe for Use With Diesel or Only Gasoline Engines?
Despite similar appearances, the unit suits gasoline systems, not diesel; diesel compatibility is not specified. The reviewer notes mixed implications for fuel efficiency and advises selecting a filter rated explicitly for diesel applications to guarantee proper protection.
Are There Any Known Compatibility Issues With Fuel Additives?
No major compatibility concerns have been reported; the filter tolerates common fuel additives, though aggressive solvent-based or high-concentration ethanol stabilizers could affect plastic components. Manufacturer guidance and additive chemical compatibility checks are recommended.
