Sierra 18-3150 Water Pump Kit, Replaces Mercury MerCruiser 46-807151A14, for Bravo and Inboard Plastic Pump Body Housings

The Sierra 18-3150 Water Pump Kit is a complete water pump rebuild kit designed for Mercury MerCruiser Bravo stern drives and inboard engines that use a plastic pump body housing, covering units with serial number 3040411 and above. The kit comes complete with a new one-piece plastic housing, impeller, stainless steel face plate, O-rings, and mounting bolts, giving you everything needed to rebuild the raw water pump in a single package rather than sourcing components separately.

The impeller is molded to Sierra's quality standards and is inspected and tested for proper bonding and performance before it leaves the factory, helping ensure consistent cooling flow once installed. Because the kit is built as an exact-fit replacement for the original equipment pump on plastic-body Bravo and inboard applications, installation time is minimized compared to sourcing mismatched parts. All components are manufactured from premium materials, including plastic, stainless steel, and steel, and are held to consistent quality standards for long-lasting performance in raw water cooling service.

This kit is intended specifically for MerCruiser Bravo and inboard engines equipped with a plastic pump body; units with a brass pump body or earlier MR/Alpha style lower units use a different Sierra part number, so confirm your pump body material and serial number before ordering.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3150
• Material: Plastic, Stainless Steel, Steel
• Weight: 1.86 pounds
• Included Components: One-piece plastic pump housing, impeller, stainless steel face plate, O-rings, mounting bolts
• Application: Bravo and inboard engines with plastic pump body, serial number 3040411 and above
• Item Type: Water Pump Kit

Fitment

• Mercury MerCruiser Bravo stern drives and inboard engines with a plastic pump body, serial number 3040411 and above

Replaces (OEM)

• Mercury MerCruiser 46-807151A14
• Mercury MerCruiser 46-807151A7
• GLM 12088
• Mallory 9-48350

Frequently Asked Questions

What does the Sierra 18-3150 Water Pump Kit include? It includes a new one-piece plastic pump housing, impeller, stainless steel face plate, O-rings, and mounting bolts, giving you everything needed to rebuild the raw water pump in one kit.

What engines does the 18-3150 fit? This kit fits Mercury MerCruiser Bravo stern drives and inboard engines that use a plastic pump body, covering units with serial number 3040411 and above.

Does 18-3150 work on units with a brass pump body? No, units with a brass pump body use a different Sierra part number; the 18-3150 is built specifically for the plastic pump body housing.

What OEM part numbers does the 18-3150 replace? The 18-3150 replaces Mercury MerCruiser 46-807151A14 and 46-807151A7, as well as GLM 12088 and Mallory 9-48350.

How much does the 18-3150 water pump kit weigh? The Sierra 18-3150 kit weighs 1.86 pounds.

Is the impeller in this kit tested for quality? Yes, the impeller in the 18-3150 kit is molded and then inspected and tested for proper bonding and performance before shipping.

What materials are used in the 18-3150 kit? The kit is made from plastic, stainless steel, and steel components, including the plastic housing and stainless steel face plate.

Will this kit fit MR or Alpha style lower units? No, MR and Alpha style lower units use different Sierra part numbers; the 18-3150 is designated for Bravo and inboard engines with a plastic pump body.

Is the 18-3150 an exact-fit replacement? Yes, it is designed as an exact-fit replacement for the original equipment pump on applicable plastic-body Bravo and inboard units, which minimizes installation labor.

How do I know if my engine needs the plastic body or brass body kit? Check your pump body material and serial number against your engine before ordering, since the 18-3150 is for plastic pump body units serial number 3040411 and above while brass pump body units require a different part number.

Is the Sierra 18-3150 covered by a warranty? Yes, the 18-3150 is covered under Sierra's warranty against defects in workmanship and materials for the useful life of the product.