Sierra 18-0240 Water Pump Gasket | Yamaha Outboard Motors | Aftermarket Replacement
Sierra 18-0240 Water Pump Gasket | Yamaha Outboard Motors | Aftermarket Replacement
Sierra
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Sierra 18-0240 — Water Pump Gasket | Yamaha Outboard Motors | Aftermarket Replacement
Sierra 18-0240 is an aftermarket water pump gasket for Yamaha outboard motors. Water pump gaskets seal the water pump housing and plate connections in the lower unit cooling system. Replacing the water pump gasket during impeller service is best practice — reusing an old gasket risks cooling system leaks and overheating after reassembly. Sierra is a leading manufacturer of aftermarket marine replacement parts cross-referenced to OEM specifications. Sold individually — confirm the quantity required for your specific outboard model before ordering. Contact us with your Yamaha outboard model and year and we’ll verify 18-0240 is the correct gasket for your application before you order.
Confirm Fitment Before Ordering
Confirm your Yamaha outboard model and year before ordering. Contact us by email, text, or live chat with your engine model and serial number and we’ll verify 18-0240 is the correct water pump gasket for your application.
Part Specifications
- Sierra Part Number: 18-0240
- Component: Water pump gasket
- Application: Yamaha outboard motors
- Type: Aftermarket replacement
- Sold: Individually
- Vendor: Sierra Marine
Additional Information
- Vendor: Sierra Marine
- Part Number: 18-0240
- Application: Yamaha outboard motors
- Component: Water pump gasket
- Sold: Individually
Installation Notes
Replace the water pump gasket any time the water pump housing is disassembled for impeller or pump service. Follow the applicable Yamaha outboard service manual for your engine model. Do not reuse previously installed gaskets.
Frequently Asked Questions
Q: What Yamaha outboard does Sierra 18-0240 fit?
A: Sierra 18-0240 is listed as a water pump gasket for Yamaha outboard motors. Contact us with your Yamaha outboard model and year and we’ll confirm whether 18-0240 is the correct gasket for your specific engine before you order.
Q: Should I replace the water pump gasket when I replace the impeller?
A: Yes — replacing the water pump gasket during every impeller service is best practice. A reused gasket may not seal correctly after reassembly, which can result in cooling system leaks or reduced water flow that leads to engine overheating. At $3.95, a new gasket is inexpensive insurance.
Q: Is Sierra 18-0240 an OEM Yamaha part?
A: No — Sierra 18-0240 is an aftermarket replacement part manufactured by Sierra Marine to cross-reference the OEM Yamaha specification. Sierra is a trusted aftermarket supplier for Yamaha and other major outboard brands.
Q: How many gaskets are included in this listing?
A: Sierra 18-0240 is sold individually as a single gasket. If your water pump service kit requires more than one gasket, order the quantity needed for your specific Yamaha model.
Q: Can I use Sierra 18-0240 gasket with a non-Sierra water pump impeller kit?
A: Yes — water pump gaskets are not impeller-brand specific. Sierra 18-0240 is a sealing component and will work alongside OEM or other aftermarket water pump kits, provided it is the correct gasket for your Yamaha outboard model.
! Compatibility references are provided for informational purposes only and do not constitute a fitment guarantee. Part numbers, application listings, and "replaces" cross-references are based on manufacturer data and are intended as a starting point for identification — not a guarantee of fit for your specific engine, hull, or installation.
Buyer is solely responsible for verifying compatibility with their engine model, serial number, model year, and trim configuration before purchase. If you are unsure whether this part fits your application, contact MacombMarineParts.com before you buy — we're available via text, email, or online chat to help verify compatibility for your specific application.
MacombMarineParts.com is not liable for parts ordered based on assumed fitment. Returns due to buyer-selected incorrect fitment are subject to our standard return and restocking fee policies.