Sea Water Pump – Fits Volvo Penta, MerCruiser, OMC 4.3L, 5.0L, 5.7L V6/V8 (Replaces 3853850, 8M0113734)
Sea Water Pump – Fits Volvo Penta, MerCruiser, OMC 4.3L, 5.0L, 5.7L V6/V8 (Replaces 3853850, 8M0113734) 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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Sea Water Pump – Fits Volvo Penta, MerCruiser, OMC 4.3L, 5.0L, 5.7L...
Sea Water Pump – Fits Volvo Penta, MerCruiser, OMC 4.3L, 5.0L, 5.7L V6/V8 (Replaces 3853850, 8M0113734) is backordered and will ship as soon as it is back in stock.
Product Details
This is a replacement Sea Water Pump – Fits Volvo Penta, MerCruiser, OMC 4.3L, 5.0L, 5.7L V6/V8 engines. Designed as a bi-directional circulation pump for raw water cooling systems, it is compatible with a wide range of GM V6/V8 marine engines from brands including Volvo Penta (1973+), MerCruiser (1963–2014), OMC (1968–1998), Indmar, Pleasurecraft, and Chrysler.
It serves as a direct replacement for MerCruiser 8M0113734/3853850, Volvo Penta 3853850, OMC 3853850, and Sierra 18-3599-2.
- Installation is engine-mounted with brass fittings.
- Features a robust steel housing with a stainless steel back plate and impeller cover.
- This assembly includes the sea water pump and a gasket set for installation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| MerCruiser | 8M0113734 |
| MerCruiser | 3853850 |
| Volvo Penta | 3853850 |
| OMC | 3853850 |
| Sierra | 18-3599-2 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This pump is designed for MerCruiser sterndrive/inboard 4.3L V6, 5.0L V8, and 5.7L V8 engines from 1963 to 2014. It is not applicable to 4.3L engines made in 2008 or later.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | 4.3L V6 | 140-200 HP | 4-Stroke | Up to 2007 | 8M0113734/3853850 | Not applicable to 2008+ 4.3L engines |
| MerCruiser | 5.0L V8 | 155-205 HP | 4-Stroke | All years | 8M0113734/3853850 | |
| MerCruiser | 5.7L V8 | 230-260 HP | 4-Stroke | All years | 8M0113734/3853850 | |
| MerCruiser | 6.2L V8 | 260+ HP | 4-Stroke | All years | 8M0113734/3853850 |
Fits Volvo Penta 4.3GL, 4.3GXi, 5.0GL, 5.0GXi, 5.7GL, and 5.7GXi engines manufactured in 1973 and later.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Volvo Penta | 4.3GL, 4.3GXi | 190-225 HP | 4-Stroke | 1973 and later | 3853850 |
| Volvo Penta | 5.0GL, 5.0GXi | 200+ HP | 4-Stroke | 1973 and later | 3853850 |
| Volvo Penta | 5.7GL, 5.7GXi | 250+ HP | 4-Stroke | 1973 and later | 3853850 |
Compatible with OMC sterndrive/inboard V6/V8 engines produced between 1968 and 1998.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| OMC | 4.3L V6 | 140-200 HP | 4-Stroke | 1968–1998 | 3853850 |
| OMC | 5.0L V8 | 155-205 HP | 4-Stroke | 1968–1998 | 3853850 |
| OMC | 5.7L V8 | 230-260 HP | 4-Stroke | 1968–1998 | 3853850 |
Also fits small block cooling systems for Indmar, Chrysler, and Pleasurecraft V6/V8 engines.
| Brand | Model | Rated HP | Stroke |
|---|---|---|---|
| Indmar | 4.3L, 5.0L, 5.7L | 140-260 HP | 4-Stroke |
| Chrysler | 4.3L, 5.0L, 5.7L | 140-260 HP | 4-Stroke |
| Pleasurecraft | Small Block V6/V8 | 140-260 HP | 4-Stroke |
Technical Specs
- Product Type
- Sea Water Circulation Pump
- Installation
- Engine-mounted
- Connection
- Brass fittings
- Housing Material
- Steel with stainless steel back plate
- Housing Color
- Black
- Fitting Type
- Brass tubes
- Warranty
- Lifetime (from certain sellers)
- Other Technical Attributes
- Bi-directional design, stainless steel impeller cover
What’s in the Box
- 1 x Sea Water Pump Assembly (8M0113734/3853850)
- 1 x Gasket Set (18-0891)
Installation Notes
- Ensure the engine is off and cool. Disconnect the battery.
- Close the seacock to prevent water from entering the boat.
- Place a container below the pump to catch any residual water. Loosen hose clamps and disconnect the inlet and outlet hoses.
- Remove the mounting bolts holding the old pump to the engine block.
- Carefully remove the old pump and clean the mounting surface on the engine, ensuring the old gasket material is completely removed.
- Position the new gasket and pump assembly onto the engine block.
- Install and tighten the mounting bolts to the manufacturer-specified torque.
- Reconnect the hoses and tighten the hose clamps securely.
- Open the seacock and reconnect the battery.
- Start the engine and check for leaks at all connections. Monitor engine temperature to ensure proper cooling system operation.
Troubleshooting & FAQ
How do I know if this pump fits my specific engine?
First, check the compatibility tables on this page. This pump fits most GM-based V6 and V8 marine engines from MerCruiser, Volvo Penta, and OMC within the specified years. The most important step is to cross-reference the part number (e.g., 3853850, 8M0113734) with your engine's service manual or the number on your existing pump.
Is this pump bi-directional?
Yes, this is a bi-directional pump, meaning it can be installed on engines with either standard (left-hand) or reverse (right-hand) rotation without modification.
What are the signs of a failing sea water pump?
Common symptoms include the engine overheating at idle or low speeds, a visible water leak from the pump housing or weep hole, reduced water flow from the exhaust, or a rattling/grinding noise coming from the pump assembly. Any of these signs warrant an immediate inspection.
My boat has a 2010 MerCruiser 4.3L engine. Will this fit?
No. As noted in the compatibility chart, this pump is not applicable to MerCruiser 4.3L V6 engines manufactured in 2008 or later.
What is the recommended maintenance for this pump?
The internal impeller is the primary wear item. It is recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of operation, depending on usage conditions (e.g., saltwater vs. freshwater). Also, regularly check for leaks and ensure hose connections are secure.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 facility, with batch-inspections for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
This product is 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 if the item is unused and in its original condition. See our policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against 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 quality control.
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