Sierra 18-3507 Water Pump Kit without Base - Replaces Mercury Marine 46-60366A1 for Mercury/Mariner Engines

The Sierra 18-3507 Water Pump Kit is a complete rebuild kit for Mercury/Mariner outboard and sterndrive water pumps, supplying every wear component needed to restore proper cooling system pressure except the pump base, which is sold separately. Rebuilding a water pump with the correct impeller, housing, gaskets, and o-rings restores raw water flow to the engine and helps prevent overheating caused by a worn or cracked impeller, a scored pump housing, or hardened gaskets that no longer seal.

This kit includes a new impeller, an impeller plate, an upper water pump housing, drain screw gaskets, a rubber washer, multiple water pump and base gaskets, and o-rings, giving an installer everything required to fully renew the pump above the base plate. Sierra manufactures the kit to meet or exceed the original equipment components it replaces, and each part is fit specific, so confirming part numbers before ordering is recommended to ensure proper fit.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3507
• Product Name: Water Pump Kit (Without Base)
• Weight: 0.35 pounds
• Material: Rubber (impeller, gaskets, o-rings)
• Compatible Engine Brand: Mercury/Mariner
• Base Included: No
• UPC: 030999315977
• OEM Cross Reference: 46-60366A1
• Kit Contents: Impeller (18-3007), Impeller Plate (18-3107), Upper Water Pump Housing (18-3118), O-Ring (35-30271), Lower Water Pump Gasket (18-2823), Water Pump Gasket (18-2824), Water Pump Base Gasket (18-2825), Water Pump Base Gasket (18-2841), Drain Screw Gaskets x2 (18-2945), Rubber Washer (18-2948), O-Rings (18-7115, 18-7155, 18-7174)

Fitment

Designed for use with Mercury/Mariner engines. This kit does not include the water pump base; verify part numbers against your existing pump components before ordering.

Replaces (OEM)

• 46-60366A1

Frequently Asked Questions

What does the Sierra 18-3507 Water Pump Kit include? The 18-3507 kit includes an impeller, an impeller plate, an upper water pump housing, a rubber washer, multiple water pump and base gaskets, drain screw gaskets, and several o-rings, covering every wear part in a Mercury/Mariner water pump rebuild except the base.

Does the 18-3507 kit come with a water pump base? No, the Sierra 18-3507 is a Water Pump Kit without Base, so the base plate is not included and must be sourced separately if it needs replacement.

What engines is the Sierra 18-3507 designed for? This kit is designed for use with Mercury/Mariner engines that use a compatible water pump assembly; checking existing part numbers before ordering is recommended since fit is specific.

What OEM part number does Sierra 18-3507 replace? Sierra 18-3507 replaces Mercury Marine part number 46-60366A1.

How much does the Sierra 18-3507 Water Pump Kit weigh? The kit weighs 0.35 pounds.

What material is the impeller and gaskets made from in the 18-3507 kit? The impeller, gaskets, and o-rings in the 18-3507 kit are made of rubber.

Is the Sierra 18-3507 a genuine Mercury part or aftermarket? The 18-3507 is a Sierra-manufactured aftermarket kit built to meet or exceed the original equipment part it replaces, rather than a genuine Mercury Marine part.

What is the impeller part number included in the 18-3507 kit? The impeller included in the Sierra 18-3507 kit is part number 18-3007.

How many drain screw gaskets come in the 18-3507 kit? Two drain screw gaskets, part number 18-2945, are included in the Sierra 18-3507 Water Pump Kit.

Why is it important to check part numbers before installing the 18-3507 kit? Because the Sierra 18-3507 kit is fit specific to certain Mercury/Mariner water pump configurations, confirming part numbers against your existing components before installation helps ensure proper fit and sealing.