Sierra 18-7802 Fuel Filter, Replaces 35-87946A3, for Mercury/Mariner Outboard 6 HP thru 25 HP

The Sierra 18-7802 is a replacement fuel filter engineered for Mercury and Mariner outboard motors from 6 HP thru 25 HP. It is built to fit the under-cowl fuel filter assemblies that use a screw-on bowl, restoring clean fuel delivery to the carburetor and protecting the engine from debris and contaminants that can cause rough running, stalling, or fuel system wear. The filter includes the filter screen and a Viton seal, giving it strong resistance to fuel and heat exposure in the demanding marine environment.

Sierra manufactures this filter to meet or exceed the performance of the original equipment part it replaces, and it is designed as a direct fit for the outboard fuel filter housings covered by this part number. Whether you are performing routine maintenance or replacing a clogged or deteriorated filter, the 18-7802 restores factory-level fuel filtration so your outboard receives consistent, clean fuel flow.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-7802
• Product Type: Fuel Filter
• Weight: 0.02 pounds
• Micron Rating: 75
• Includes: Fuel filter screen and Viton seal
• Fitment: Mercury/Mariner outboard, 6 HP thru 25 HP

Fitment

• Mercury/Mariner outboard motors, 6 HP thru 25 HP

Replaces (OEM)

• 35-87946A3
• 35-87946-Q3
• 35-87946-Q4

Frequently Asked Questions

What does the Sierra 18-7802 fuel filter fit? The Sierra 18-7802 fits Mercury/Mariner outboard motors from 6 HP thru 25 HP.

Is the 18-7802 a direct OEM replacement? Yes, the 18-7802 replaces OEM numbers 35-87946A3, 35-87946-Q3, and 35-87946-Q4, and it is designed to meet or exceed the performance of the original filter it replaces.

What is included with the Sierra 18-7802? The Sierra 18-7802 includes the fuel filter screen and a Viton seal for the under-cowl fuel filter assembly.

What micron rating does this fuel filter have? The 18-7802 has a micron rating of 75, filtering out particulate contamination before it reaches the carburetor.

How much does the Sierra 18-7802 fuel filter weigh? This filter weighs 0.02 pounds.

What type of seal does the 18-7802 use? A Viton seal is used on the Sierra 18-7802, chosen for its resistance to fuel and heat in marine applications.

Does the 18-7802 work with screw-on bowl fuel filter housings? Yes, the 18-7802 is built for Mercury under-cowl fuel filter assemblies that use a screw-on bowl.

Which OEM part numbers does the Sierra 18-7802 cross-reference to? The 18-7802 replaces OEM numbers 35-87946A3, 35-87946-Q3, and 35-87946-Q4.

Is the Sierra 18-7802 suitable for regular maintenance replacement? Yes, the 18-7802 is intended as a routine replacement fuel filter for Mercury/Mariner outboards in the 6 HP thru 25 HP range.

Why replace a fuel filter like the 18-7802 regularly? A worn or clogged fuel filter can restrict fuel flow and cause rough running or stalling; replacing it with the Sierra 18-7802 restores clean fuel delivery to the carburetor.