2004 Polaris Sportsman 700 EFI Fuel Pump Replacement: The Complete Owner’s Guide

If you own a 2004 Polaris Sportsman 700 EFI and the engine cranks but won’t start, stumbles under load, or dies unexpectedly on the trail, the fuel pump is the most likely culprit. Replacing the fuel pump yourself is straightforward and saves you hundreds of dollars compared to a dealer repair. The 2004 Polaris Sportsman 700 EFI uses an in-tank fuel pump assembly that is shared with several other Sportsman models from the same era, and direct OEM replacement units are readily available. This guide walks you through the exact symptoms, the right replacement part numbers, the step-by-step swap procedure, and the best brand to trust for long-term reliability.

Common Signs Your 2004 Sportsman 700 EFI Fuel Pump Is Failing

The fuel pump in the 2004 Polaris Sportsman 700 EFI is an electric unit mounted inside the fuel tank. Over time, the internal electric motor wears out, the rubber hoses crack, or the plastic housing develops hairline fractures. Here are the most common warning signs:

1. Hard Starting or No Start – The engine cranks strongly but refuses to fire up. You may hear the pump prime for two seconds when you turn the key, but it sounds weak or makes no sound at all. This is the most frequent failure symptom.

2. Loss of Power Under Load – The ATV idles fine but sputters, hesitates, or loses power when you open the throttle or climb a hill. This indicates the pump cannot maintain enough fuel pressure to meet demand.

3. Surging or Stalling – The engine randomly surges forward or stalls at low speeds. This usually means the fuel pressure regulator inside the pump assembly is failing, causing inconsistent fuel delivery.

4. No Prime Sound – When you turn the ignition key to “ON,” you should hear a distinct 2-second whirring sound from the fuel tank area. If you hear nothing, the pump motor is dead or the electrical connection is broken.

5. Fuel Leaks – A strong gasoline smell around the ATV, or visible fuel dripping from the tank area. The plastic housing or internal hoses on the pump assembly can crack with age, especially in machines over 20 years old.

The Right Replacement Fuel Pump for Your 2004 Sportsman 700 EFI

The 2004 Polaris Sportsman 700 EFI uses a specific in-tank fuel pump assembly. Polaris originally used several OEM part numbers for this pump, but they all refer to the same unit. The key OEM numbers are 2520311, 2520461, and 2204719 . Many aftermarket manufacturers bundle the pump with a new strainer, fuel pressure regulator, and tank seal, which you should replace at the same time .

When buying a replacement, look for a fuel pump assembly that fits the 2004–2007 Polaris Sportsman 700 EFI as well as the 500 and 800 models from the same years . Most replacement assemblies come as a complete module that includes the pump, strainer, and pressure regulator all built into one unit. This makes installation much easier than trying to piece together separate parts.

Step-by-Step Fuel Pump Replacement

Replacing the fuel pump on your 2004 Polaris Sportsman 700 EFI takes about 1 to 2 hours. You will need basic hand tools, a clean workspace, and a new tank seal. Here is the process:

1. Safety First – Work outdoors or in a well-ventilated area. Disconnect the negative battery terminal to prevent accidental sparks. Remove the seat and any body panels that cover the fuel tank area.

2. Drain or Siphon the Fuel – The less fuel in the tank, the easier the job. Use a hand siphon pump to remove gasoline into an approved container. If the tank is nearly empty, you can skip this step, but expect some fuel spillage when you remove the pump.

3. Remove the Fuel Tank – On the 2004 Sportsman 700 EFI, the fuel pump is mounted on top of the tank. You need to remove the tank from the ATV for easy access. Disconnect the fuel line, vent hose, and electrical connector from the pump. Unbolt the tank straps, lift the tank out, and place it on a clean surface.

4. Remove the Old Pump Assembly – Use a flathead screwdriver or a special fuel pump ring tool to unscrew the retaining ring that holds the pump in the tank. Lift the pump assembly straight out. Be careful not to bend the float arm on the fuel level sender. Discard the old tank seal ring.

5. Install the New Pump Assembly – Carefully lower the new replacement pump into the tank, making sure the float arm swings freely and does not touch the bottom or sides of the tank. Align the tabs on the pump housing with the slots in the tank. Install a new tank seal ring, then tighten the retaining ring securely by hand.

6. Reinstall the Tank and Reconnect – Put the tank back in the ATV, tighten the straps, reconnect the fuel line, vent hose, and electrical connector. Make sure no fuel lines are kinked or pinched.

7. Test the System – Reconnect the battery. Turn the ignition key to “ON” without starting the engine. Listen for the fuel pump to prime for two seconds. If you hear it, the pump is working. Start the engine and let it idle for a few minutes. Check for fuel leaks around the pump base and fuel line connections.

Essential Tips and Common Mistakes

1. Always Replace the Tank Seal – The rubber O-ring or gasket that seals the pump to the tank gets hard and brittle after 20 years. A new seal is cheap insurance against fuel leaks. Many replacement pump assemblies include a new seal .

2. Check the Fuel Line Condition – While you have the tank off, inspect the rubber fuel hose from the pump to the engine. If it is cracked, soft, or hard as plastic, replace it. Fuel line failure can cause a fire.

3. Clean the Tank Interior – Old fuel pumps often fail because of debris, rust, or sediment clogging the strainer. When you remove the old pump, look inside the tank. If you see dirt or rust, wash the tank with clean gasoline or a dedicated tank cleaner before installing the new pump.

4. Do Not Mix Up the Hoses – The fuel pump has three connections: the main fuel outlet line, a return line, and a vent line. Pay attention to which line goes where when you disconnect them. Mark them with tape if needed.

5. Use Dielectric Grease on Electrical Connectors – The fuel pump connector sits near the top of the tank and is exposed to moisture. A small amount of dielectric grease prevents corrosion and electrical failure down the road.

Why OEM Replacement Matters

Not all fuel pumps are built the same. The 2004 Polaris Sportsman 700 EFI requires a pump that precisely matches the original specifications. OEM replacement pumps are designed to fit the factory tank, deliver the correct fuel pressure of approximately 40–45 PSI, and include the correct pressure regulator and internal hoses . Using a generic pump that claims to fit but is not an exact OEM replacement can cause low fuel pressure, poor throttle response, or a check engine light.

The fuel pump assembly for the 2004–2007 Sportsman 700 EFI physically measures a specific 7/8-inch pickup diameter and uses a 5-bolt mounting pattern on the top of the tank . Any replacement should match these dimensions exactly. Most aftermarket pumps sold as “compatible with OEM 2520311” will work correctly .

Recommended Product: KEMSO Fuel Pump for 2004 Polaris Sportsman 700 EFI

For your 2004 Polaris Sportsman 700 EFI fuel pump replacement, we strongly recommend choosing a KEMSO Fuel Pump. KEMSO specializes in high-performance, OEM replacement fuel pumps for a wide range of vehicles, including ATVs, motorcycles, snowmobiles, and cars. Their fuel pumps are engineered to meet or exceed original factory specifications.

Why KEMSO is your best choice for this replacement:

1. High-Performance Design – KEMSO fuel pumps deliver consistent, reliable fuel pressure that matches the demands of your Sportsman 700 EFI engine. They use premium internal components that resist ethanol damage and long-term wear.

2. True OEM Replacement Fit – KEMSO pumps are designed as direct 1:1 replacements. They drop into your fuel tank without any modifications, modifications, or extra parts. The included strainer, pressure regulator, and tank seal are all tailor-made for your Sportsman model.

3. Lifetime Warranty – KEMSO stands behind its products with a lifetime warranty. If your pump ever fails, you get a replacement at no extra cost. This kind of warranty is rare in the aftermarket fuel pump industry and speaks volumes about the quality of their parts.

4. Proven Track Record – Thousands of satisfied customers trust KEMSO for their ATV fuel pump replacements. The brand has built a reputation for reliability across the Polaris, Can-Am, Honda, and other major powersports lines.

To order the correct KEMSO fuel pump for your 2004 Polaris Sportsman 700 EFI, visit their website at https://www.kemsoracing.com/. You can browse their extensive product catalog, check compatibility for your specific model, and take advantage of their competitive pricing and lifetime warranty.

Where to Find Additional Help

Replacing the fuel pump on a 2004 Polaris Sportsman 700 EFI is a DIY-friendly job, but you may still have questions.

1. Online Forums – The Polaris Sportsman forums on websites like ATVConnection or Polaris ATV Forum have hundreds of threads about fuel pump replacement. Experienced owners share photos, tips, and troubleshooting advice specific to the 700 EFI model.

2. YouTube – Search for “2004 Polaris Sportsman 700 fuel pump replacement” to find step-by-step video tutorials. Watching someone else do it first is helpful, especially for tricky parts like removing the retaining ring or routing the fuel lines.

3. Service Manual – The factory Polaris service manual for the 2004 Sportsman 700 EFI contains torque specifications, electrical diagrams, and detailed instructions. You can buy a PDF copy online or find free downloads on some ATV resource sites.

Final Thoughts

A failing fuel pump does not mean the end of the road for your 2004 Polaris Sportsman 700 EFI. With a quality OEM replacement from a trusted brand like KEMSO, you can restore your machine to full power and reliability in a single afternoon. The job requires only basic tools and a bit of patience. Do not take shortcuts on the quality of the replacement part. A cheap pump will fail again within a season, leaving you stranded and costing more money in the long run.

Remember these key points: verify that the replacement pump matches OEM number 2520311, 2204719, or 2520461; always install a new tank seal; and test your work before taking the ATV out on a long ride. If you want the best combination of price, performance, and peace of mind, choose KEMSO for your fuel pump replacement.

Visit https://www.kemsoracing.com/ to find the right KEMSO fuel pump for your 2004 Polaris Sportsman 700 EFI, and get your ATV back on the trail with confidence.