Sierra Marine Water Pump Kit 18-3150 – MerCruiser Bravo / TRS Complete Cooling System Rebuild
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
The Sierra 18-3150 Water Pump Kit is a complete seawater pump rebuild kit designed for MerCruiser Bravo and TRS sterndrives and inboard engines with one-piece pump housings. This kit includes all critical components needed to fully restore raw water pump performance and ensure proper engine cooling.
Built to meet or exceed OEM specifications, this kit features a new one-piece housing, impeller, wear plate, seals, and hardware—providing a complete solution for servicing worn or failing cooling systems.
Replacing the entire pump assembly ensures optimal water flow, improved reliability, and protection against overheating in demanding marine environments.
Key Features
- Complete raw water pump rebuild kit
- Includes housing, impeller, wear plate, O-rings, and hardware
- Designed for one-piece seawater pump housings
- Restores full cooling system performance
- OEM-equivalent fit and function
- Durable marine-grade components
- Sierra limited lifetime warranty
Engine Compatibility
MerCruiser Sterndrives & Inboards
- Bravo I
- Bravo II
- Bravo III
- TRS drives
- Select MerCruiser inboard engines
➡️ Designed specifically for 1-piece water pump housing systems
Serial Number Fitment Notice
Fitment depends on:
- Drive type (Bravo / TRS)
- Pump housing design (1-piece vs 2-piece)
- Engine serial number
⚠️ Always confirm using:
- Engine serial number
- OEM part number match (18-3150)
When This Part Needs Replacement
Replace the water pump kit if you notice:
- Engine overheating
- Weak or inconsistent water flow
- Impeller damage or wear
- Leaks from pump housing
- Scheduled maintenance interval
Recommended service interval: every 100 hours or annually (impeller), full kit as needed
Installation Notes
- Ensure correct housing type (1-piece system required)
- Lubricate impeller during installation
- Replace all included seals and O-rings
- Inspect pump cavity and mating surfaces
- Torque bolts to manufacturer specifications
Alternate / Superseded Part Numbers
OEM Cross References
- Mercury / MerCruiser: 46-807151A14, 46-807151A7
Aftermarket Cross References
- Sierra: 18-3150
- GLM: 12088
- Mallory: 9-48350
What’s Included in the Kit
- One-piece plastic pump housing
- Impeller (Sierra 18-3087)
- Stainless steel wear plate
- O-rings and seals
- Mounting hardware (bolts)
Shipping
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
💡 Parts Desk Insight
If your Bravo drive pump hasn’t been rebuilt in a few seasons, it’s not just the impeller—you’re usually dealing with worn housings and sealing surfaces too.
Doing the full kit instead of just the impeller restores proper water pressure and can prevent repeat failures 👍
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.