S2K Commerce - Products Dropdown
Actions
S2K Commerce - Order Entry
Actions
Mercury Outboard Parts
Shop OEM and aftermarket Mercury outboard parts for maintenance, repair, troubleshooting, and complete engine rebuild projects. Browse Mercury marine parts by system, including cooling, fuel delivery, electrical and ignition, internal engine components, lower unit parts, steering, trim, and routine service items.
Pro Marine USA carries Mercury outboard engine parts for a wide range of 2-stroke, FourStroke, EFI, Optimax, Pro XS, SeaPro, and Verado applications. Use your engine horsepower, model, serial number, or OEM part number whenever possible to confirm fitment before ordering.
Shop Mercury Outboard Parts by System
- Complete Powerheads
- Control Cables & Boxes
- Cooling System
- Cowlings & Components
- Electrical System
- Engine Oil
- Engine Rebuild Kits
- Fuel & Carburetion System
- Intake System
- Internal Engine Components
- Lower Unit Components
- Oiling System
- Paints
- Service & Oil Change Kits
- Service Manuals
- Steering Systems
- Throttle Components
- Transom & Midsection
- Trim System
- Wizard Performance Parts
Find the Correct Mercury Outboard Part
Mercury outboard parts can vary by horsepower, engine family, model year, and serial number range. If you are unsure which component fits your engine, use the OEM parts lookup to locate the original Mercury part number from an engine diagram.
Once you have the OEM part number, search Pro Marine to find available genuine Mercury and aftermarket replacement options.
Use Our OEM Parts Lookup »Common Mercury Outboard Engine Families
Pro Marine supports many Mercury outboard applications across a wide horsepower range. Always confirm the engine serial number and model information before ordering parts.
- Portable and Midrange: Mercury 2.5HP through 60HP 2-stroke and FourStroke applications
- FourStroke and EFI: common 75HP through 300HP Mercury EFI and FourStroke platforms
- Pro XS: performance-oriented Mercury Pro XS outboards across multiple engine families
- Optimax: direct-injected 2-stroke Mercury Optimax engines, commonly 75HP through 250HP
- Verado: supercharged and naturally aspirated Mercury Verado applications from 135HP through current high-horsepower platforms
- SeaPro: commercial-duty Mercury SeaPro outboards used in professional and high-hour applications
Common Mercury Outboard Repair Areas
- Overheating: inspect the water pump, impeller, thermostat, poppet valve, cooling passages, and related cooling components.
- Hard starting or rough running: inspect fuel pumps, filters, injectors or carburetors, spark plugs, coils, sensors, and intake components.
- No spark or intermittent ignition: check ignition coils, stators, switch boxes, trigger assemblies, sensors, grounds, and wiring.
- Low compression or power loss: inspect pistons, rings, cylinders, bearings, gaskets, reeds, and internal engine components.
- Lower unit noise or water intrusion: inspect seals, bearings, gears, shafts, bearing carriers, and gear lube condition.
- Trim or steering problems: inspect trim motors, pumps, hydraulic components, steering cylinders, hoses, and related rigging parts.
Why Buy Mercury Outboard Parts from Pro Marine USA?
- OEM Mercury and aftermarket replacement options for many common applications.
- Parts for maintenance, repair, engine rebuilding, lower units, electrical systems, fuel systems, steering, trim, and rigging.
- OEM diagram and part-number lookup tools to help identify the correct part before ordering.
- Dealer pricing available for qualified marine repair businesses and dealers.
- Large inventory of Mercury service parts and hard-to-find marine engine components.
- Fast weekday shipping on qualifying in-stock orders.
Frequently Asked Questions
How do I find the correct Mercury outboard part?
Use the engine horsepower, model, serial number, and year whenever available. Mercury frequently uses serial-number ranges to identify engine families, so the serial number is often the most reliable way to confirm fitment.
Can I search Mercury parts by OEM part number?
Yes. Enter the Mercury OEM part number into the Pro Marine site search to locate available OEM and aftermarket replacement options. If you do not know the part number, use the OEM parts lookup first.
Do Mercury outboard parts vary by serial number?
Yes. Many Mercury components change by serial-number range even within the same horsepower or model family. Always compare the serial range listed for the part with your engine before ordering.
Do you carry parts for Mercury Optimax and Verado engines?
Yes. Pro Marine carries parts for many Mercury Optimax, Verado, Pro XS, EFI, FourStroke, and SeaPro applications, including maintenance, fuel, electrical, cooling, internal engine, lower unit, steering, and rigging components.
Do you carry both OEM and aftermarket Mercury parts?
Yes. Pro Marine offers genuine Mercury parts along with aftermarket replacement parts for many common Mercury outboard maintenance, repair, and rebuild applications.
What Mercury outboard parts are commonly replaced during routine maintenance?
Common maintenance items include engine oil, oil filters, fuel filters, spark plugs, water pump kits, impellers, thermostats, gear lube, drain plug seals, anodes, and manufacturer-specific service kit components.
Fitment Tip: Mercury outboard parts often vary by serial-number range. Confirm your engine serial number and OEM part number whenever possible before ordering.
Sierra Marine Fuel / Water Separator Filter
Sierra 18-7920 Fuel / Water Separator - 10 Micron - 1"-12 Thread
The Sierra 18-7920 Fuel / Water Separator is a 10-micron spin-on replacement filter designed for universal marine fuel filtration applications using a 1"-12 thread.
This filter uses the large center-hole configuration and is designed to help remove water and fine contaminants from the fuel supply before they reach the engine.
Sierra 18-7920 cross references popular Mercury, Johnson / Evinrude, OMC, Racor and Fram fuel / water separator numbers listed below.
Thread: 1"-12
Filtration: 10 Micron
Style: Spin-On Replacement
Application: Universal Marine
Specifications
| Specification | Details |
|---|---|
| Manufacturer | Sierra |
| Sierra Part Number | 18-7920 |
| Filter Type | Fuel / Water Separator |
| Filtration Rating | 10 Micron |
| Thread Pitch | 1"-12 |
| Configuration | Large Center Hole |
| Replacement Style | Spin-On |
| Application | Universal Marine |
OEM & Cross Reference Numbers
| Manufacturer / Brand | Part Number |
|---|---|
| Sierra | 18-7920 |
| Fram | CH33APL |
| Johnson / Evinrude Outboard | 771839 |
| Mercury Marine | 35-809099 |
| OMC Stern Drive | 771839 |
| Racor | B32014 |
| Racor | S3214 |
Universal Marine Application
Sierra 18-7920 is a universal replacement fuel / water separator filter for compatible marine filter heads using a 1"-12 threaded filter.
Because this filter is used across multiple marine engine brands and fuel systems, fitment should be determined by the filter-head thread and the existing filter cross-reference number rather than by engine horsepower alone.
This is the large-hole 1"-12 thread style fuel / water separator.
Compare your existing filter number and filter-head thread before ordering. Marine fuel separator filters may look very similar while using different center-hole sizes or thread pitches.
What a Fuel / Water Separator Does
A marine fuel / water separator helps protect the engine fuel system by removing water and particulate contamination before the fuel reaches the engine.
Water can enter a marine fuel system through condensation, contaminated fuel or moisture in the tank. The separator provides an additional stage of filtration before the engine-mounted fuel filter or fuel injection system.
10-Micron Filtration
The Sierra 18-7920 is rated at 10 microns, allowing it to capture fine fuel contaminants while separating water from the fuel supply.
Maintaining a clean fuel / water separator can help reduce the chance of restricted fuel flow and contamination reaching carburetors, fuel pumps or fuel injection components.
When Should a Fuel / Water Separator Be Replaced?
Replacement intervals vary based on engine use, fuel quality and operating conditions. Fuel / water separator filters should be inspected and replaced as part of regular marine engine maintenance.
Replacement should also be considered whenever contaminated fuel or water in the fuel system is suspected.
Common Reasons for Replacement
- Routine annual or seasonal maintenance
- Water found in the fuel system
- Contaminated or stale fuel
- Restricted fuel flow
- Engine fuel starvation symptoms
- Unknown age of the existing fuel separator
- Replacing Fram CH33APL
- Replacing Johnson / Evinrude or OMC 771839
- Replacing Mercury 35-809099
- Replacing Racor B32014 or S3214
Installation Notes
Confirm that the filter head uses the correct 1"-12 thread before installation.
Follow the engine or filter-head manufacturer's installation procedure. Inspect the filter-head sealing surface and make sure the old filter gasket has been completely removed before installing the replacement.
Key Features and Benefits
- Sierra marine replacement fuel / water separator
- Sierra part number 18-7920
- 10-micron filtration rating
- 1"-12 thread pitch
- Large center-hole configuration
- Spin-on replacement design
- Universal marine application
- Replaces Fram CH33APL
- Replaces Johnson / Evinrude 771839
- Replaces OMC 771839
- Replaces Mercury 35-809099
- Replaces Racor B32014
- Replaces Racor S3214
- Helps remove water and contaminants from marine fuel
FAQ
What is the micron rating of Sierra 18-7920?
The Sierra 18-7920 is a 10-micron fuel / water separator.
What thread does Sierra 18-7920 use?
It uses a 1"-12 thread.
Is this the large-hole fuel / water separator?
Yes. Sierra 18-7920 is the large center-hole configuration.
Is Sierra 18-7920 a spin-on filter?
Yes. It is a spin-on replacement fuel / water separator.
What Mercury filter does Sierra 18-7920 replace?
It cross references Mercury Marine 35-809099.
What Johnson / Evinrude or OMC number does it replace?
It replaces 771839.
What Racor filters does it replace?
It cross references Racor B32014 and S3214.
What Fram filter does it replace?
It cross references Fram CH33APL.
Is this filter engine-specific?
No. It has a universal marine application for compatible
filter heads using the correct 1"-12 thread.
How do I know if this filter fits my boat?
Compare the existing filter part number and verify that your filter head
uses a 1"-12 thread. Cross-reference numbers are listed above.
Dealer Discounts & Store Policies
Dealer / Marine Industry Discounts
Are you a marine dealer, technician, boat builder, or industry professional? We offer dealer pricing for qualified marine businesses.
Shipping Policy
- Free shipping on orders over $100 continental U.S.
- Orders received before 5:30 PM EST ship the same business day.
- Typical delivery time is 1-5 business days.
30-Day Return Policy
- Returns accepted within 30 days of delivery.
- Parts must be new, unused, and in original packaging.
- Installed parts are not returnable.
- Return authorization is required before sending items back.
Need help verifying the correct fuel separator?
Contact Pro Marine
Phone: 941-721-3000
Searchable Terms
18-7920, Sierra 18-7920, Sierra fuel water separator, Sierra water separator filter, marine fuel water separator, marine fuel filter, 10 micron fuel filter, 10 micron water separator, 1-12 fuel filter, 1 inch 12 thread fuel filter, large hole fuel water separator, spin on marine fuel filter, universal marine fuel separator, CH33APL, Fram CH33APL, 771839, Evinrude 771839, Johnson 771839, OMC 771839, 35-809099, Mercury 35-809099, Mercury fuel water separator, B32014, Racor B32014, S3214, Racor S3214, boat fuel water separator, outboard fuel separator, sterndrive fuel separator
0002507
0771839
18-7920
MAR-FLTHD-10-BK
9-37862
0360941
0398319
0435918
0765595
0777715
18-7831
18-7831
311679
360941
398319
40165
765595
777715
802128A1
55481
89876
89876A3
9-37855
16910-ZVL-003
8M0153652
879885K
879885Q
879885T
18-7853-1
55481
89876
89876A3
35-809097
8M0103095
8M0146203
809097