Fuel Pump Diaphragm Kit – Fits Mercury/Mariner/Force 30-275 HP (Replaces 857005A1, 42990A10)
Fuel Pump Diaphragm Kit – Fits Mercury/Mariner/Force 30-275 HP (Replaces 857005A1, 42990A10) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Fuel Pump Diaphragm Kit – Fits Mercury/Mariner/Force 30-275 HP (Rep...
Product Details
This Fuel Pump Diaphragm Kit – Fits Mercury/Mariner/Force 30-275 HP (Replaces 857005A1, 42990A10) is designed to restore fuel system performance in a wide range of outboards. It is compatible with Mercury/Mariner 30-275 HP 2-stroke models (1978–1999) and select 4-stroke engines featuring square or triangular fuel pumps, as well as Force/Chrysler 40-150 HP 2-stroke outboards (1991–1999).
The kit serves as a direct interchange for multiple OEM and aftermarket part numbers, including Mercury 857005A1 and the 42990A series, Sierra 18-7817, GLM 40290, and EMP 1399-39020.
- Installs as a direct replacement for the original diaphragm.
- Engineered for gasoline fuel systems.
- Includes essential components for a complete rebuild.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 857005A1 |
| Mercury | 42990A10 |
| Mercury | 42990A9 |
| Mercury | 42990A8 |
| Mercury | 42990A7 |
| Mercury | 42990A6 |
| Mercury | 42990A5 |
| Mercury | 42990A4 |
| Mercury | 42990A3 |
| Mercury | 42990A2 |
| Mercury | 42990A1 |
| Sierra | 18-7817 |
| GLM | 40290 |
| EMP | 1399-39020 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury/Mariner 4-stroke models, compatibility is limited to engines equipped with square or triangular style fuel pumps.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 30 (2 Cyl.) | 30 | 2-Stroke | 1987–1998 | 857005A1 | Serial #0G055314-0G760299 (USA) |
| Mercury | 30 (2 Cyl.) | 30 | 2-Stroke | 857005A1 | Serial #9854537-0P016999 (Belgium) | |
| Mercury | 30 Jet (3 Cyl.) | 30 | 2-Stroke | 857005A1 | Serial #0G590000-0G760299 (USA) | |
| Mercury | 30 Jet (3 Cyl.) | 30 | 2-Stroke | 857005A1 | Serial #9973100-0P016999 (Belgium) | |
| Mercury | 30 Jet | 30 | 2-Stroke | 857005A1 | Serial #0C159200-0G589999 (USA) | |
| Mercury | 35 | 35 | 2-Stroke | 1987–1989 | 857005A1 | |
| Mercury | 40 (2 Cyl.) | 40 | 2-Stroke | 1994–1998 | 857005A1 | |
| Mercury | 40 (3 Cyl.) | 40 | 2-Stroke | 1997–1998 | 857005A1 | |
| Mercury | 45 | 45 | 2-Stroke | 1987–1989 | 857005A1 | |
| Mercury | 45 Jet | 45 | 2-Stroke | 1994–1995 | 857005A1 | |
| Mercury | 50 | 50 | 2-Stroke | 1988–1998 | 857005A1 | |
| Mercury | 55 | 55 | 2-Stroke | 1996–1997 | 857005A1 | |
| Mercury | 75 (4 Cyl.) | 75 | 2-Stroke | 1984–1988 | 857005A1 | |
| Mercury | 75 (3 Cyl.) | 75 | 2-Stroke | 1990–1998 | 857005A1 | |
| Mercury | 80 Jet | 80 | 2-Stroke | 857005A1 | ||
| Mercury | 90 (6 Cyl.) | 90 | 2-Stroke | 1979–1986 | 857005A1 | |
| Mercury | 90 (3 Cyl.) | 90 | 2-Stroke | 1987 | 857005A1 | |
| Mercury | 100 (4 Cyl.) | 100 | 2-Stroke | 1988–1998 | 857005A1 | |
| Mercury | 115 | 115 | 2-Stroke | 1979–1998 | 857005A1 | |
| Mercury | 125 | 125 | 2-Stroke | 1994–1998 | 857005A1 | |
| Mercury | V-135 | 135 | 2-Stroke | 1986–1995 | 857005A1 | |
| Mercury | V-135 DFI | 135 | 2-Stroke | 1998 | 857005A1 | |
| Mercury | V-150 | 150 | 2-Stroke | 1978–1985, 1986+ | 857005A1 | |
| Mercury | V-220 Laser | 220 | 2-Stroke | 1987–1988 | 857005A1 | |
| Mercury | V-225 3.0L | 225 | 2-Stroke | 1994–1998 | 857005A1 | |
| Mercury | V-250 3.4L | 250 | 2-Stroke | 1989–1994 | 857005A1 | |
| Mariner | 75 | 75 | 2-Stroke | 857005A1 | ||
| Mariner | 90 | 90 | 2-Stroke | 857005A1 | ||
| Mariner | 100 [ELPTO] | 100 | 2-Stroke | 1987–1998 | 857005A1 | |
| Mariner | 115 [ELPTO] | 115 | 2-Stroke | 1987–1999 | 857005A1 | |
| Mariner | 125 [ELPTO] | 125 | 2-Stroke | 1994–1998 | 857005A1 | |
| Mariner | 135 | 135 | 2-Stroke | 1986–1998 | 857005A1 | |
| Mariner | 150 | 150 | 2-Stroke | 1978–1999 | 857005A1 | |
| Mariner | 175 | 175 | 2-Stroke | 1978–1999 | 857005A1 | |
| Mariner | 200 | 200 | 2-Stroke | 1978–1999 | 857005A1 | |
| Mariner | 220XRI | 220 | 2-Stroke | 1987–1988 | 857005A1 | |
| Mariner | 225 | 225 | 2-Stroke | 1994–1998 | 857005A1 | |
| Mariner | 250 | 250 | 2-Stroke | 1989–1994 | 857005A1 | |
| Mariner | 275 | 275 | 2-Stroke | 1994–1997 | 857005A1 |
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Force | 40 | 40 | 2-Stroke | 1992–1999 | 857005A1 | |
| Force | 50 | 50 | 2-Stroke | 1992–1999 | 857005A1 | |
| Force | 70 | 70 | 2-Stroke | 1992–1995 | 857005A1 | |
| Force | 75 | 75 | 2-Stroke | 1996–1999 | 857005A1 | |
| Force | 90 | 90 | 2-Stroke | 1992–1999 | 857005A1 | |
| Force | 120 | 120 | 2-Stroke | 1991–1999 | 857005A1 | |
| Force | 150 | 150 | 2-Stroke | 1993–1994 | 857005A1 |
Technical Specs
- Product Type
- Fuel Pump Diaphragm Kit
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Other Technical Attributes
- ISO9002 certified factory production (JLM Marine)
What’s in the Box
- 1 x Spring
- 1 x Cap
Installation Notes
- Disconnect the battery and relieve any pressure from the fuel system.
- Locate and access the fuel pump assembly on your engine.
- Carefully remove the screws holding the fuel pump cover and separate the housing.
- Remove the old diaphragm, gaskets, and other components being replaced. Note their orientation.
- Clean the housing surfaces to ensure a proper seal.
- Install the new diaphragm, check valves, gaskets, and spring from the kit.
- Reassemble the fuel pump housing and tighten screws to the manufacturer's specified torque.
- Reconnect the fuel lines, prime the system, and check for leaks before starting the engine.
Troubleshooting & FAQ
How do I know if this kit fits my 4-stroke engine?
This kit is primarily for 2-stroke models. It only fits 4-stroke Mercury/Mariner outboards that use a specific square or triangular-shaped mechanical fuel pump. Visually inspect your pump before ordering.
What are the symptoms of a failing fuel pump diaphragm?
Common signs include engine bogging down under acceleration, difficulty starting, rough idling, fuel starvation at high speeds, or visible fuel leaking from the pump's weep hole.
Is there a recommended replacement interval for this part?
While there is no fixed interval, it is good practice to inspect the fuel pump and diaphragm during regular annual service. Replace it at the first sign of cracking, stiffness, or leakage to prevent fuel delivery failure.
Can I buy just the diaphragm without the full kit?
This product is sold as a complete kit, including gaskets and other essential hardware. This ensures all necessary wear components are replaced at the same time for a reliable repair.
Will this kit fix an oil leak on my V6 engine?
This is a fuel pump diaphragm kit and will not typically resolve oil leaks. If your V6 Mercury/Mariner has an oil leak in the fuel pump area, you may need a different seal or are having an unrelated issue.
Does this kit fit Force engines made by Chrysler?
Yes, it is designed for Force outboards from 1991 to 1999, which were manufactured after Chrysler's marine division was acquired. The compatibility tables above list the specific models.
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 a 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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