Water Pump Impeller Kit – Fits MerCruiser Bravo 1, 2, 3 & Inboard Engines 4.3L-7.4L V8

Water Pump Impeller Kit – Fits MerCruiser Bravo 1, 2, 3 & Inboard Engines 4.3L-7.4L V8Water Pump Impeller Kit Fits MerCruiser Bravo 1, 2, 3 & Inboard Engines 4. 3L 7. 4L V8 This water pump impeller service kit is designed for MerCruiser Bravo 1, 2, 3 sterndrives and inboard engines. It is compatible with 4. 3L, 5. 0L, 5. 7L, and 7. 4L V8 engines manufactured from 1988 and up (serial number B664190 and up) that are equipped with a one piece pump housing and a serpentine belt. This kit serves as a direct replacement for multiple OEM and

Water Pump Impeller Kit – Fits MerCruiser Bravo 1, 2, 3 & Inboard Engines 4.3L-7.4L V8

This water pump impeller service kit is designed for MerCruiser Bravo 1, 2, 3 sterndrives and inboard engines. It is compatible with 4.3L, 5.0L, 5.7L, and 7.4L V8 engines manufactured from 1988 and up (serial number B664190 and up) that are equipped with a one-piece pump housing and a serpentine belt.

This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, ensuring a precise fit for your engine's raw water cooling system.

• Complete Kit: Includes the impeller, wear plate, and O-ring(s) needed for a full service.
• Durable Material: The impeller is made from high-quality neoprene rubber for reliable performance in raw water/sea water applications.
• Engine-Mounted Design: Specifically for engine-mounted, one-piece pump housings.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (Replaces 18-3087)
• 1 x Wear Plate (Replaces 18-3350)
• 1-2 x O-Ring(s) (Replaces 18-7163-9) - Note: Kit may contain one or two O-rings.

Installation Guide

Follow these general steps to replace your water pump impeller. Refer to your engine’s service manual for detailed instructions.

1. Disconnect Power: Disconnect the battery to prevent accidental starting.
2. Access the Pump: Locate the raw water pump on the engine. It is typically belt-driven. You may need to remove a serpentine belt to access it.
3. Remove Hoses: Loosen the clamps and detach the inlet and outlet water hoses from the pump housing.
4. Remove Pump Housing: Unscrew the bolts securing the pump housing cover or the entire pump assembly. Keep track of bolt order and length.
5. Extract Old Impeller: Carefully remove the old impeller from the housing. You may need impeller pullers or pliers. Note the orientation of the blades.
6. Clean Housing: Clean the inside of the housing and the wear plate of any debris, corrosion, or old gasket material. Inspect for scoring or damage.
7. Install New Components: Install the new wear plate and O-ring/gasket. Lightly lubricate the new impeller with water or soap and insert it while turning it in the direction of engine rotation to bend the vanes correctly.
8. Reassemble Housing: Secure the housing cover, ensuring an even seal. Tighten bolts to the manufacturer's recommended torque.
9. Reconnect Hoses & Belt: Reattach the water hoses and the serpentine belt, ensuring proper tension.
10. Test for Leaks: Reconnect the battery. Start the engine and immediately check for proper water flow and any leaks around the pump housing.

Troubleshooting & FAQ

Q: How do I confirm this impeller kit fits my specific MerCruiser engine?
A: Start by checking your engine's model, year, and serial number against the "Compatible Engine Models" table above. This kit is for models from 1988 and up (Serial #B664190+) with a one-piece pump housing and serpentine belt. Cross-reference your existing part number with our "Part Number Cross-Reference" table to ensure it matches.

Q: What are the signs of a failing water pump impeller?
A: Common signs include the engine running hotter than normal, a "low water pressure" alarm, and a reduced stream of water from the exhaust/tell-tale outlet. Visual inspection may show cracked, brittle, or missing vanes on the impeller.

Q: How often should I replace my water pump impeller?
A: For preventative maintenance, it is recommended to inspect the impeller annually and replace it every 1-2 years, or every 100-200 hours of operation, depending on usage conditions (e.g., saltwater vs. freshwater).

Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.