Carburetor Rebuild Kit – Fits Mercury/Mariner 40-150 HP (Replaces 1395-5109-1, 18-7021)
Carburetor Rebuild Kit – Fits Mercury/Mariner 40-150 HP (Replaces 1395-5109-1, 18-7021) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Carburetor Rebuild Kit – Fits Mercury/Mariner 40-150 HP (Replaces 1...
Carburetor Rebuild Kit – Fits Mercury/Mariner 40-150 HP (Replaces 1395-5109-1, 18-7021) is backordered and will ship as soon as it is back in stock.
Product Details
This comprehensive Carburetor Rebuild Kit – Fits Mercury/Mariner 40-150 HP provides all essential components to restore a single carburetor on 2-stroke outboard engines from 1976–1990 with specific WMK series designations. It ensures your engine receives the correct fuel-air mixture for reliable performance.
It serves as a direct interchange for Mercury part 1395-5109-1, Sierra 18-7021, GLM 40480, and Pro Marine 7021.
- Designed for a direct replacement of OEM service components.
- Includes all necessary gaskets, seals, and a needle valve for a complete overhaul of one carburetor.
- Note: Three kits are required to service engines with a three-carburetor setup.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 1395-5109 / 1395-5109-1 |
| Sierra | 18-7021 |
| GLM | 40480 |
| Pro Marine | 7021 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is compatible with specific Mercury and Mariner outboard engines equipped with WMK-series carburetors manufactured between 1976 and 1990.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Mercury | WMK series 1.8, 21, 24, 31, 33, 34, 38 | 40 | 2-Stroke | 1976–1990 | 1395-5109-1 |
| Mercury | WMK 8 | 50 | 2-Stroke | 1976–1990 | 1395-5109-1 |
| Mercury | WMK 5, 12, 13, 20 | 65 (650) | 2-Stroke | 1976–1990 | 1395-5109-1 |
| Mercury | WMK 4, 16, 17 | 85 (850) | 2-Stroke | 1976–1990 | 1395-5109-1 |
| Mercury | WMK 23, 27, 30, 35, 39 | 90 (900) | 2-Stroke | 1976–1990 | 1395-5109-1 |
| Mercury | WMK 3, 10, 15, 18, 26, 28, 32, 36, 40, 41 | 115 (1150) | 2-Stroke | 1976–1990 | 1395-5109-1 |
| Mercury | WMK 4 | 135 (1350) | 2-Stroke | 1976–1990 | 1395-5109-1 |
| Mercury | WMK 7, 9, 25, 29 | 140 (1400) | 2-Stroke | 1976–1990 | 1395-5109-1 |
| Mercury | WMK 11, 14, 19, 22 | 150 (1500) | 2-Stroke | 1976–1990 | 1395-5109-1 |
Technical Specs
- Product Type
- Carburetor Rebuild Kit
- Installation
- Direct replacement for OEM service
- Fuel Type
- Gasoline
- Weight
- 21 g (0.74 oz)
- Package Dimensions
- 18 × 15 × 2 cm
- Warranty
- 1-year against manufacturing defects
What’s in the Box
- Complete rebuild kit for a single carburetor.
- Premium gaskets and O-rings
- Needle valve assembly
- Float pivot pin
- Other essential small components for service (contents may vary slightly by manufacturer)
Installation Notes
- Ensure the engine is off and the fuel supply is shut off before beginning work. Work in a well-ventilated area.
- Carefully remove the carburetor(s) from the engine, noting the location of all linkages and fuel lines.
- Disassemble the carburetor, cleaning all metal components with a dedicated carburetor cleaner. Do not use cleaner on rubber or plastic parts.
- Systematically replace old gaskets, seals, and the needle valve with the new components from the kit.
- Reassemble the carburetor, ensuring the float is set to the manufacturer's specified height.
- Reinstall the carburetor(s) on the engine. For engines with multiple carburetors, it is recommended to service all at the same time. Note: Three kits are required to rebuild all carburetors on a 3-carburetor engine.
- After installation, check for leaks and adjust the idle and mixture screws as necessary.
Troubleshooting & FAQ
How many kits do I need for my engine?
Each kit services one carburetor. If your engine has multiple carburetors (e.g., many inline-6 models), you will need to purchase one kit per carburetor for a complete overhaul.
Does this kit fit all Mercury/Mariner engines from 40-150 HP?
No. This kit is specifically for models from 1976–1990 that use WMK-series carburetors. Please verify your carburetor model number or check our compatibility table to ensure a match.
What are the signs my carburetor needs to be rebuilt?
Common symptoms include hard starting, rough idling, stalling, poor acceleration, black smoke from the exhaust, or fuel leaking from the carburetor body. These indicate that internal seals have degraded or passages are clogged.
Does this kit include a new float?
This kit includes the float pivot pin and needle valve assembly, but not the float itself. Floats are typically sold separately as they are not always required for a standard rebuild.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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