Fuel Pump for Mercury/Mariner 4-Stroke 4–6 HP Outboard Engines – Replaces 803529T06, 803529T01, 803529T02, 803529T03 and 3H6-04000-7
Fuel Pump for Mercury/Mariner 4-Stroke 4–6 HP Outboard Engines – Replaces 803529T06, 803529T01, 803529T02, 803529T03 and 3H6-04000-7 is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
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Fuel Pump for Mercury/Mariner 4-Stroke 4–6 HP Outboard Engines – Re...
Fuel Pump for Mercury/Mariner 4-Stroke 4–6 HP Outboard Engines – Replaces 803529T06, 803529T01, 803529T02, 803529T03 and 3H6-04000-7 is backordered and will ship as soon as it is back in stock.
Product Details
This replacement mechanical fuel pump is listed for Mercury and Mariner 4-stroke 4 HP, 5 HP, and 6 HP outboard engines. It is intended to replace a worn or damaged pump when the original part number and engine configuration match the references shown below.
The listed replacement references are Mercury/Mariner part numbers 803529T06, 803529T01, 803529T02, and 803529T03, together with Tohatsu part number 3H6-04000-7. Always compare the number on your existing pump and confirm the complete engine model information before ordering.
- Replacement fuel pump for selected small 4-stroke outboard applications.
- Mechanical operation for engine-driven fuel delivery.
- Plastic-and-metal housing construction.
- Single replacement fuel pump supplied.
Part Number Matrix
Use the matrix below as a reference when comparing the original pump with this replacement.
| Brand | Part Number |
|---|---|
| Mercury/Mariner | 803529T06 |
| Mercury/Mariner | 803529T01 |
| Mercury/Mariner | 803529T02 |
| Mercury/Mariner | 803529T03 |
| Tohatsu | 3H6-04000-7 |
Engine & Model Compatibility
The applications below reflect the listed 4-stroke horsepower range and reference numbers. Model year, exact model designation, serial number, mounting arrangement, and fuel-system configuration may affect fitment. Confirm the original part number before installation.
| Brand | Rated HP | Stroke | Reference Part No. |
|---|---|---|---|
| Mercury | 4 HP | 4-Stroke | 803529T06, 803529T01, 803529T02, 803529T03 |
| Mercury | 5 HP | 4-Stroke | 803529T06, 803529T01, 803529T02, 803529T03 |
| Mercury | 6 HP | 4-Stroke | 803529T06, 803529T01, 803529T02, 803529T03 |
| Mariner | 4 HP | 4-Stroke | 803529T06, 803529T01, 803529T02, 803529T03 |
| Mariner | 5 HP | 4-Stroke | 803529T06, 803529T01, 803529T02, 803529T03 |
| Mariner | 6 HP | 4-Stroke | 803529T06, 803529T01, 803529T02, 803529T03 |
| Tohatsu | 4 HP | 4-Stroke | 3H6-04000-7 |
| Tohatsu | 5 HP | 4-Stroke | 3H6-04000-7 |
| Tohatsu | 6 HP | 4-Stroke | 3H6-04000-7 |
Technical Specs
- Product Type
- Mechanical fuel pump
- Installation
- Replacement installation for a matching original pump
- Fuel Type
- Gasoline
- Connection
- Hose barb
- Housing Material
- Plastic and metal
- Housing Color
- Black
- Fitting Type
- Vehicle-specific fit
- Operation
- Mechanical
What's in the Box
- 1 x Replacement mechanical fuel pump
Only the fuel pump is included. Fuel lines, clamps, mounting hardware, gaskets, and other installation components are not specified as included unless shown or stated separately.
Installation Notes
- Ensure the engine is switched off and completely cool before beginning work.
- Work in a well-ventilated area away from flames, sparks, and other ignition sources.
- Relieve fuel-system pressure as appropriate and place absorbent material around the fuel lines to catch spills.
- Note the routing and orientation of each fuel line before disconnecting the old pump.
- Remove the old pump and clean the mounting surface without allowing debris to enter the fuel system.
- Install the replacement pump in the correct orientation and tighten the mounting fasteners according to the engine manufacturer's specifications.
- Reconnect the fuel lines to the correct ports and secure them with suitable clamps where required.
- Prime the fuel system if necessary, inspect all connections for leaks, and verify proper operation before returning the engine to service.
Follow the service manual for your exact engine model. Professional installation is recommended if you are not familiar with marine fuel systems.
Troubleshooting & FAQ
How do I confirm this fits my specific engine?
Compare the part number on your existing pump with 803529T06, 803529T01, 803529T02, 803529T03, or 3H6-04000-7. Also verify the engine brand, 4-stroke configuration, horsepower, model designation, and serial-number range where applicable. A general 4–6 HP match alone is not sufficient to confirm every engine application.
What are common signs of a failing fuel pump?
Possible symptoms include hard starting, stalling, fuel starvation, loss of power, uneven running, or visible fuel leakage. Inspect the complete fuel system before replacing the pump, since restricted filters, damaged hoses, tank contamination, or carburetor problems can cause similar symptoms.
Is maintenance required?
The mechanical pump itself is not normally serviced as a routine maintenance item. Keep the fuel system clean, replace fuel filters at the intervals specified for your engine, and inspect hoses and connections for deterioration or leaks.
Is this an OEM part?
This is an aftermarket replacement fuel pump, not a factory-branded OEM component. It is intended for applications matching the listed reference numbers and engine conditions.
What are the shipping speeds and costs?
Shipping availability, delivery estimates, and costs depend on the destination and the options displayed at checkout.
What is the warranty and return policy?
Warranty coverage and return eligibility are subject to the seller's current policy. Review the applicable policy before purchase and contact support with your order information if assistance is needed.
Safety & Important Information
- Verify the original part number and the complete engine application before ordering.
- Do not operate the engine if fuel leaks are present.
- Use appropriate personal protective equipment and work in a well-ventilated area.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for fuel-system work.
About Sea Sierra
- Marine Replacement Parts — We supply replacement components for a range of recreational and service applications.
- Application-Focused Support — Compare the original part number and engine details to help identify the correct replacement.
- Direct-Value Products — Practical aftermarket alternatives for routine repair and maintenance needs.
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