Mercury Mariner Outboard Piston Kit 35-150HP 774-9137A11 18-4530 2.875" Bore
91371
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Piston Kit for Mercury Mariner Outboards
Precision Replacement Part (SKU: 91371)
This premium quality piston kit is engineered to provide a direct-fit replacement for Mercury and Mariner 2-stroke outboard engines. Specifically designed for the 35HP to 150HP range (1970–1990), this kit features a low-dome piston manufactured from a high-silicon content aluminum alloy. This material ensures exceptional thermal stability, reduced expansion, and extended service life in demanding marine environments.
Key Features
- ✔ Direct fit for 35-150HP 2-stroke models
- ✔ High-silicon aluminum alloy material
- ✔ Interchangeable with OEM components
- ✔ Low-dome crossflow design
Technical Specs
| Bore Size: | 2.875" (Std) / 2.905" (.030) |
| Piston Type: | Low Dome |
| Kit Includes: | Piston, Rings, Pin, Clips |
| Application: | 2-Stroke Outboard |
Compatibility / Fitment Guide
| Engine Type | Cylinders | Year Range |
|---|---|---|
| 35 HP / 40 HP | 2-Cylinder | 1972 – 1989 |
| 50 HP / 60 HP / 70 HP | 3-Cylinder | 1973 – 1990 |
| 75 HP / 80 HP / 85 HP | 4-Cylinder | 1973 – 1986 |
| 90 HP / 115 HP / 140 HP | 6-Cylinder | 1970 – 1988 |
OEM Cross Reference
| Mercury / Mariner | 774-9137A11, 774-9137A10, 774-9137A9 |
| Sierra Marine | 18-4530 |
| Mallory Marine | 9-53401 |
Questions & Answers
Is this a genuine original part?
This is a premium quality aftermarket replacement part, manufactured to meet or exceed original equipment (OE) standards for fitment and performance.
How do I know if it is compatible?
We recommend checking your original part number against the cross-reference list provided above. This kit is specifically for the 3-port crossflow engines common in the 1970s and 80s.
Do I need to replace all pistons at once?
No, this kit is designed with the same weight and balance as the original OEM components, meaning you can replace individual pistons as needed without necessarily replacing the entire set.
Note: Please verify your original engine serial number and part number against the references above before purchasing to ensure correct fitment. Visit 4boats.co.uk for further assistance.
For the products under £150 the shipping is £6.99.
Free delivery for most items over £150.
