Sierra 18-48317 Complete Water Pump Kit, Replaces 46-803750A03, Fits Mercury/Mariner 8-9.9 HP 4-Stroke

The Sierra 18-48317 is a complete water pump kit engineered as a direct replacement for the cooling system on Mercury/Mariner 8-9.9 HP 4-Stroke (209cc) outboards (R042475 & Up). The kit restores proper raw water flow to the powerhead, preventing the overheating that follows a worn or cracked impeller, a hardened housing gasket, or a corroded wear plate. Because it is supplied as a complete kit rather than a single component, it lets an installer replace every wear item in the water pump assembly in one job instead of ordering parts piecemeal and risking a mismatch.

Sierra builds this kit to meet or exceed the specifications of the original equipment part it replaces, and it is backed by Sierra's standard limited warranty. It is designed to bolt in as a direct fitment replacement for the Mercury/Mariner 8-9.9 HP 4-Stroke application listed above.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-48317
• Product Name: Complete Water Pump Kit
• Material: Metal
• Weight: 0.81 pounds
• Vehicle Service Type: Boat
• Unit Count: 1

Fitment

• Mercury 8-9.9 HP 4-Stroke (209cc) (R042475 & Up)

Replaces (OEM)

• 46-803750A03

Frequently Asked Questions

What does the Sierra 18-48317 kit include? The Sierra 18-48317 is a complete water pump kit, supplying the full set of components needed to rebuild the water pump assembly rather than a single part such as just the impeller.

Which engines does the 18-48317 water pump kit fit? This kit fits Mercury 8-9.9 HP 4-Stroke (209cc) outboards with serial number R042475 and up.

What OEM part number does the 18-48317 replace? The Sierra 18-48317 replaces Mercury OEM part number 46-803750A03.

How much does the 18-48317 water pump kit weigh? It weighs 0.81 pounds.

What material is the Sierra 18-48317 kit made of? The kit is made of metal.

Is the Sierra 18-48317 a genuine Mercury part or an aftermarket part? It is an aftermarket Sierra part manufactured to meet or exceed the specifications of the original Mercury equipment part it replaces, part number 46-803750A03.

How many water pump kits come in one Sierra 18-48317 package? Each package contains one complete water pump kit, a unit count of 1.

Does the 18-48317 kit come with a warranty? Yes, the Sierra 18-48317 is covered under Sierra's standard limited warranty.

Will the 18-48317 kit work on any Mercury outboard? No, it is designed specifically for Mercury 8-9.9 HP 4-Stroke (209cc) outboards with serial number R042475 and up, not all Mercury models.

Why replace the water pump with a complete kit instead of just the impeller? A complete kit like the Sierra 18-48317 replaces all of the wear components in the water pump assembly at once, reducing the chance of a repeat cooling system failure from an overlooked worn part.