Yamaha Rhino 660 Fuel Pump: Comprehensive Guide to Issues, Diagnosis, Replacement & Maintenance

The Yamaha Rhino 660 fuel pump is a critical component responsible for delivering gasoline from the tank to the engine under consistent pressure. Failure of this pump manifests through distinct symptoms like hard starting, stalling, loss of power, or the engine not starting at all. Diagnosing issues accurately often involves checking electrical connections, fuel pressure, and the pump assembly itself. Replacing a faulty Yamaha Rhino 660 fuel pump is a moderately challenging but achievable DIY task requiring careful removal of the fuel tank. Regular maintenance, particularly using clean fuel and replacing the fuel filter, is essential for optimal longevity and performance of this vital part. Neglecting fuel pump health can lead to frustrating breakdowns and potential engine damage. Understanding its function, recognizing failure signs, and knowing your repair options are crucial for every Rhino 660 owner ensuring reliable operation.

Understanding the Yamaha Rhino 660 Fuel Pump's Role

• Core Function: The fuel pump is the heart of the fuel delivery system. Its sole purpose is to draw gasoline from the fuel tank and push it through the fuel lines to the fuel injectors at a specific, consistent pressure.
• Pressurized Delivery: Modern fuel-injected engines like the Rhino 660’s require fuel to be delivered under high pressure (typically around 36-38 PSI for these models) for the injectors to atomize the fuel properly. The pump creates and maintains this critical pressure.
• Electric Operation: The Rhino 660 uses an electric fuel pump submerged inside the fuel tank (often referred to as a "submersible" or "in-tank" pump). This design helps cool the pump motor and reduces vapor lock risk. It’s powered by the vehicle’s electrical system when the ignition is turned on.
• Integrated Components: The fuel pump assembly includes more than just the pump motor itself. It typically consists of:
  • The Pump Motor: The electric motor that generates the pumping action.
  • Fuel Level Sending Unit: A float arm and sensor that measures the amount of fuel in the tank and sends this information to the fuel gauge on the dashboard.
  • Inlet Strainer/Sock: A pre-filter attached to the pump inlet inside the tank. This coarse mesh filter traps large contaminants (like debris, rust flakes, or sediment) before they reach the pump. It is the first line of defense.
  • Fuel Pressure Regulator (Often Integrated): Some pump assemblies include a pressure regulator to ensure fuel is delivered at the correct pressure to the injectors, bypassing excess fuel back to the tank. In other designs, the regulator is mounted on the fuel rail.
  • Outlet Fittings/Tubing: Connects the pump assembly to the main fuel line running to the engine.
• Dependence on Other Systems: The pump relies on a clean fuel supply, good electrical connections (including proper voltage and ground), and intact fuel lines. Its performance directly impacts the fuel injectors' ability to function correctly and the engine's ability to run smoothly and powerfully.

Common Symptoms of a Failing or Bad Yamaha Rhino 660 Fuel Pump

Identifying pump issues early can prevent being stranded or causing further damage. Watch for these signs:

1. Engine Cranks But Won't Start: This is one of the most common symptoms. If the pump isn't delivering fuel at all or at sufficient pressure, the engine will crank over normally when you turn the key or press the start button, but it won't actually fire up because no fuel is reaching the cylinders. This is distinct from a starter motor issue where the engine might turn slowly or not at all.
2. Engine Stalling, Especially Under Load: A weak pump may provide enough fuel for idling or light cruising but fail under higher demand situations like accelerating, climbing hills, or towing. The engine will suddenly lose power and stall. It might restart after cooling down for a few minutes, only to stall again once placed under load.
3. Sputtering or Loss of Power at Higher Speeds/RPMs: Similar to stalling under load, a failing pump may cause significant hesitation, sputtering, jerking, or a noticeable lack of power when you attempt to sustain higher speeds or RPMs. The engine feels like it's starving for fuel.
4. Long Cranking Times Before Starting: If the pump is weakening, it might take significantly longer cranking time to build up enough fuel pressure to start the engine than it used to.
5. Engine Surging: Unexpected and inconsistent surges in engine RPM while trying to maintain a constant speed can sometimes indicate inconsistent fuel pressure from a failing pump.
6. Noticeable Drop in Fuel Economy: While many factors affect gas mileage, a faulty pump working harder or inefficiently can contribute to a noticeable decrease in miles per gallon.
7. Loud Whining Noise from Fuel Tank: While a faint hum from the pump area after turning the key on is normal, an unusually loud whining, buzzing, or screeching noise originating near or from the fuel tank is a classic sign of a fuel pump motor struggling or nearing the end of its life.
8. Illuminated Check Engine Light: While not always triggered solely by pump failure (it could be wiring, relay, etc.), a failing pump that delivers insufficient pressure or causes fuel delivery issues can sometimes lead to trouble codes like low fuel pressure (P0087), fuel pressure sensor issues, or misfire codes (like P0300 - Random/Multiple Cylinder Misfire Detected) due to lean conditions. A diagnostic scan tool is needed to retrieve specific codes.
9. Intermittent Problems: Fuel pump failures can often be intermittent initially. It might work fine one day and cause problems the next, making diagnosis more frustrating but pointing towards electrical connections or a pump motor starting to fail.
10. Vehicle Dies When Hot ("Heat Soak"): Heat can exacerbate a failing pump. If your Rhino consistently starts and runs fine cold but stalls and dies once the engine or ambient temperatures are high, a weak pump struggling to maintain pressure could be the culprit.

Diagnosing Yamaha Rhino 660 Fuel Pump Problems

Before condemning the pump itself, perform systematic checks to rule out simpler issues:

1. Visual Checks & Basics:
   • Fuel Level: Always confirm you actually have sufficient fuel in the tank! Gauges can be inaccurate.
   • Fuel Filter: Inspect the external in-line fuel filter (if equipped – Rhinos often have one). A severely clogged filter can mimic fuel pump failure symptoms by restricting flow. Replace if old or dirty; it’s a cheap and essential maintenance item.
   • Battery Health: Ensure the battery is fully charged. A weak battery can cause sluggish cranking that might be misinterpreted, and provides insufficient voltage to run the pump optimally.
   • Fuses & Connections: Locate the fuse box and visually inspect the fuel pump fuse. Use a multimeter to test it for continuity. Check related fuses. Inspect wiring harness connections going to the fuel tank for obvious damage, corrosion, or looseness.
2. Fuel Pump Power Circuit Test:
   • Listen for Pump Prime: Have an assistant turn the ignition key to the "ON" position (but do not start the engine). Place your ear near the fuel tank area. You should hear a distinct whirring or humming sound from the fuel pump lasting for 1-3 seconds as it primes the system. No sound does not definitively mean the pump is bad – it could be a wiring, relay, or fuse issue. Note: Ensure the engine is cold/cool for safety during this test.
3. Electrical Voltage & Ground Testing (Using Multimeter):
   • Relay Test: Locate the fuel pump relay (consult service manual for location – often in the fuse box under the hood or dash). You can try swapping it with a known good identical relay (like the horn relay). If the pump starts working after the swap, the relay was faulty. Test the relay socket terminals for power and ground signals when key is turned ON. Confirm proper relay operation.
   • Voltage at the Pump Connector: This is often the most definitive electrical test but requires accessing the wiring harness connector near the fuel tank.
     • Disconnect the main electrical connector leading to the fuel pump assembly (usually near the top/rear of the tank).
     • Set your multimeter to measure DC Volts (20V range). Attach the positive (red) lead to the terminal in the connector coming from the vehicle that supplies +12V when the pump is commanded. Attach the negative (black) lead to a clean ground point on the chassis (or the corresponding ground terminal in the connector).
     • Have an assistant turn the ignition key to the "ON" position. You should see a clear 12+ volts on the meter. If not, the problem is in the wiring, fuse, or relay circuit upstream of the pump.
     • While the key is ON, check continuity/resistance between the designated ground terminal in the vehicle connector and the chassis ground. Low resistance (near 0 ohms) is required.
4. Fuel Pressure Test (Critical Diagnostic):
   • Necessary Tool: Requires a fuel pressure test kit compatible with Schrader valves (or the specific port on your Rhino's fuel rail if equipped) or test fittings that splice into the fuel line.
   • Safety First: Work in a well-ventilated area away from ignition sources. Wear safety glasses and gloves. Relieve residual fuel system pressure before disconnecting anything: Locate the fuel pump fuse or relay. Start the engine and let it idle until it stalls from fuel starvation. Crank for a few seconds to ensure pressure is depleted. Disconnect the battery negative terminal as an extra safety measure.
   • Connect Gauge: Locate the fuel pressure test port on the fuel rail (it often looks like a tire valve stem). Connect your fuel pressure gauge securely to this port according to the kit instructions.
   • Test Pressure:
     • Turn ignition ON (do not start). Observe gauge. Pressure should quickly rise to the specified pressure (usually around 36-38 PSI for the Rhino 660) and hold steady or drop very slowly.
     • Start the engine (reconnect battery if disconnected). Pressure should remain stable at specification at idle.
     • Apply engine load by quickly snapping the throttle open. Pressure should rise slightly and remain stable when throttle is held open.
     • Turn engine off. Pressure should hold relatively steady for several minutes (check service manual for exact hold spec, but a significant drop shortly after shutdown indicates a leak or faulty pressure regulator).
   • Interpreting Results: Pressure consistently below specification (especially under load), failure to build pressure, or pressure dropping rapidly after shutdown point directly towards a failing fuel pump, a stuck-open fuel pressure regulator, or a significant internal leak within the pump assembly. If voltage was confirmed at the pump connector and fuel pressure is low, the pump is highly suspect. If pressure holds after shutdown but is low during operation, the pump is likely weak.
5. Flow Rate Test (Less Common, but Possible): Some advanced diagnostics involve measuring the volume of fuel delivered over a specific time period (e.g., into a container during prime cycle), comparing it against specifications. Low flow indicates a weak pump or severe restriction.

Options for Replacement Yamaha Rhino 660 Fuel Pump

If diagnosis confirms pump failure, you have choices:

1. Genuine Yamaha OEM Pump:
   • Pros: Guaranteed to meet original specifications, perfect fit and function, highest quality control, best longevity (usually), includes all necessary seals/gaskets. Supports manufacturer engineering.
   • Cons: Significantly more expensive than aftermarket options.
2. Aftermarket Direct Replacement Pump Assemblies:
   • Pros: Much more affordable than OEM, generally designed to be direct replacements fitting stock tank/lines. Quality varies greatly by brand – research is essential! Reputable brands offer good value. Often include entire assembly (pump, sender, strainer, seals).
   • Cons: Quality can range from excellent to poor (shorter lifespan, noisy operation, fitment issues). Warranty periods and support vary. Ensure compatibility.
3. Replacement Pump Module Only: Some assemblies allow replacement of just the pump motor itself inside the housing (using a compatible part from Bosch, Denso, Walbro, etc.), rather than the entire unit. This requires transferring the sender, strainer, etc., to the new pump module.
   • Pros: Can be very cost-effective if just the pump motor fails. Access to high-quality replacement pump brands.
   • Cons: Requires careful disassembly and reassembly of the assembly. Risk of damaging components during transfer. Needs proper seals. Sender/strainer may also be worn. Requires diagnostic certainty about which part failed. Not suitable if the tank/sending unit housing is damaged.
4. Rebuilt/Refurbished Units: Less common, but exist.
   • Pros: Lower cost than new OEM.
   • Cons: Variable reliability. Warranty may be shorter. Still more expensive than many new aftermarket units. Availability limited.

Recommended Choice: For long-term reliability and peace of mind, Genuine Yamaha OEM is the top recommendation. However, high-quality aftermarket assemblies from reputable brands (e.g., Bosch, Delphi, Walbro, Carter, K&L, All Balls – research specific reviews) are a very popular and practical choice offering excellent value and performance for the Rhino 660. Avoid the cheapest no-name brands.

Step-by-Step Replacement Guide: Yamaha Rhino 660 Fuel Pump

Disclaimer: Vehicle repair involves risks. Wear appropriate safety gear (gloves, eye protection). Ensure a safe working environment (ventilation, fire extinguisher nearby). Relieve fuel pressure and disconnect the battery before any work. These are general guidelines – always consult a specific service manual for your model year for detailed procedures and torque specs.

Tools & Supplies Needed:

• New Fuel Pump Assembly (or replacement module if going that route)
• Socket wrench set (Metric sockets: 8mm, 10mm, 12mm, 14mm commonly needed)
• Screwdrivers (Flathead & Phillips)
• Pliers (Standard & Needle-nose)
• Safety Glasses & Gloves (Nitrile recommended)
• Shop Towels or Rags
• Drain Pan (2-3 gallon capacity)
• Jack & Jack Stands (or suitable Rhino lift/ramps)*
• Flat Pry Tool (Plastic or metal trim tools)
• Torque Wrench (Recommended for critical fasteners)
• Fuel Line Disconnect Tools (May be necessary depending on line type)
• Replacement In-line Fuel Filter (Good practice while system is open)
• Replacement Locking Fuel Tank Ring Tool (Often required)
• Small container for bolts/nuts
• Optional: Fuel Stabilizer, Shop Vacuum

Procedure:

1. Preparation & Safety:
   • Park the Rhino on a level surface.
   • Disconnect the negative battery terminal.
   • Relieve fuel system pressure (as described in Diagnosis section).
   • Ensure ignition key is OFF.
   • Put on safety glasses and gloves.
   • Position the drain pan beneath the fuel tank area.
2. Accessing the Fuel Pump Assembly: The pump is accessed through an access panel under the Rhino's bed liner/cover, eliminating the need to physically remove the entire tank.
   • Remove any cargo from the bed.
   • Remove the screws or fasteners securing the bed liner/cover. Lift it off carefully and set aside.
   • Locate the circular access panel in the bed floor over the fuel tank. It's typically held in place by several screws.
   • Remove the screws securing the access panel and lift it off, revealing the top of the fuel pump assembly. There may be dirt/mud – clean the area thoroughly around the pump flange before proceeding to prevent debris falling into the tank.
3. Disconnecting Components:
   • Carefully disconnect the electrical connector(s) from the pump assembly. Note positions/polarity. Press any locking tabs firmly before pulling apart.
   • Disconnect the fuel lines from the assembly. Method depends on type:
     • Quick-disconnect fittings: Depress the locking tabs/collar and pull the line off straight. Avoid twisting. Using the correct disconnect tool (size varies by fitting) makes this safer and easier, preventing damage.
     • Hose clamps: Slide off any clamps using pliers or screwdriver, then twist the hose slightly while pulling it off the barb fitting. Be prepared for residual fuel spillage.
   • Mark the lines if necessary to ensure correct reconnection (feed/return).
4. Removing the Fuel Pump Assembly:
   • You will see a large plastic locking ring securing the pump assembly to the tank flange. This ring usually has locking tabs and requires a special spanner wrench tool or a large pair of channel-lock pliers (used carefully) to rotate it counterclockwise (CCW). Important: Ensure you have the correct lock ring tool or large pliers; it can be very tight, especially if corroded. Apply steady pressure without breaking the ring or damaging the tank flange. Penetrating oil sprayed around the ring edge can help if it's stuck.
   • Once the locking ring is loosened completely, lift it off. Note the orientation of any alignment notches.
   • Carefully lift the entire pump assembly straight up and out of the tank. Tilt it slightly as needed to clear the opening. Be mindful of the float arm attached to the fuel level sender – don't bend it. Avoid letting the strainer drag debris into the pump inlet.
5. Installing the New Fuel Pump Assembly:
   • Critical Step: Compare the old and new assemblies meticulously. Ensure the new pump fits correctly, all ports align, the electrical connector matches, the float arm length/shape is the same, and the rubber gasket/seal is present and identical to the old one.
   • Transfer the Strainer?: If the new assembly didn't come with a strainer, carefully transfer the old strainer to the new pump's inlet tube. Ensure it's pushed on securely. Best practice is to always replace the strainer if available as part of the new assembly.
   • Position the new rubber seal/gasket onto the tank opening flange. Ensure it's seated perfectly in its groove and perfectly clean/dry.
   • Position the new pump assembly over the opening, aligning any orientation marks/notches present. Ensure the float arm can swing freely without binding. Gently lower it straight down into the tank, guiding the fuel lines and wiring through the opening. Seat it fully so the pump assembly flange rests on the tank flange.
   • Re-install the plastic locking ring. Align it properly with the tank flange. Use the tool or pliers to rotate the ring clockwise (CW) until it feels snug. Do not overtighten! Overtightening can crack the ring or damage the tank/pump flange. Follow any torque specs if specified in the service manual or assembly instructions. You should feel firm resistance when it's seated against the tabs/locks.
6. Reconnecting Components:
   • Reconnect the fuel lines to their correct ports on the pump assembly. Ensure they click securely into place (quick-disconnects) or are pushed fully onto the barb and secured with new hose clamps (if clamps were used).
   • Reconnect the electrical connector(s), ensuring they are fully seated and locked.
7. Optional - Replace In-line Fuel Filter: Now is an excellent time to locate and replace the external in-line fuel filter. Follow the fuel line from the tank towards the engine – it's usually clamped somewhere accessible. Replace it per filter instructions, noting flow direction.
8. Final Checks & Reassembly:
   • Visually double-check all connections are secure.
   • Clean any spilled fuel immediately. Ensure the area is dry.
   • Reinstall the circular access panel securely.
   • Reinstall the bed liner/cover.
   • Reconnect the negative battery cable.
9. Priming the System & Initial Startup:
   • Turn the ignition key to the "ON" position (do not start). Listen near the tank area. You should clearly hear the new pump whirr/prime for a few seconds. Repeat this ON-OFF cycle 2-3 times to ensure fuel fills the lines and rail properly.
   • Start the engine. It might crank slightly longer than normal initially as any remaining air purges. It should start and idle smoothly.
   • Listen Carefully: Listen for any unusual noises from the new pump. A steady hum is normal; loud whining or grinding is not.
   • Visual Inspection: Carefully inspect under the access panel area (if accessible) and around the fuel filter/lines for any leaks. Do this immediately after startup and after the engine is warm. Address any leaks instantly.
   • Check Fuel Gauge: Ensure the fuel gauge reads correctly after replacement.

Maintaining Your Yamaha Rhino 660 Fuel Pump for Longevity

Prevention is key. Prolong your new pump's life:

1. Use Clean, Quality Fuel: Contaminants and water are pump killers. Avoid questionable sources or old fuel. Ethanol blends (like E10) are acceptable if used promptly, but try to avoid storing the Rhino for long periods with ethanol fuel. Using Top-Tier detergent gasoline periodically can help keep the system clean.
2. Regularly Replace the Fuel Filter: This is crucial. Replace the external in-line fuel filter at least every 100 operating hours or once a season, whichever comes first. A clogged filter forces the pump to work harder, generating excess heat and wear. Consult your owner's manual for exact intervals. Also check/replace the internal inlet strainer sock periodically when accessing the pump. Replace strainer with every pump replacement.
3. Maintain Adequate Fuel Level: Don't constantly run the tank extremely low. The submerged pump relies on the gasoline for cooling. Running very low consistently exposes the pump motor to more heat, shortening its lifespan. Keep the tank at least 1/4 full when possible.
4. Fuel Stabilizer for Storage: If storing the Rhino for more than 30 days, add a high-quality fuel stabilizer (like STA-BIL Marine formula for ethanol resistance or SeaFoam) to a full tank of fuel. Run the engine for several minutes to circulate stabilized fuel through the entire system before storage. This prevents fuel degradation ("varnish") and corrosion inside the pump and tank. Storing with a full tank also minimizes air space where condensation can form, adding water to the fuel.
5. Avoid Running on Empty: Running completely out of fuel not only leaves you stranded but also causes the pump to run dry for at least a brief moment, which can cause immediate damage or shorten its life drastically. Refuel promptly.
6. Address Performance Issues Promptly: Ignoring symptoms like misfires, rough running, or power loss can sometimes mask underlying fuel pressure issues. Investigate promptly to prevent stressing the pump or causing other problems (like catalytic converter damage from misfires).
7. Keep the Tank Venting System Clear: A clogged tank vent can create a vacuum inside the tank as fuel is consumed, making the pump work much harder to pull fuel. If you hear a "whoosh" sound when opening the fuel cap after driving, the vent might be partially blocked. Inspect the vent hose/valve.

Common Questions (Q&A)

• Q: Where is the Yamaha Rhino 660 fuel pump located?
  • A: It's located inside the fuel tank. Access is gained by removing the bed liner/cover and then removing a circular access panel in the bed floor directly above the tank. This avoids removing the entire fuel tank.
• Q: Is there a Yamaha Rhino 660 fuel pump fuse? Where is it?
  • A: Yes. There is a fuse dedicated to the fuel pump circuit. Its location is typically in the main fuse box under the hood or sometimes under the driver's side front body panel. Consult the specific diagram in your Rhino's owner's manual or on the fuse box lid. It's often a 15A or 20A fuse.
• Q: Can I clean the Yamaha Rhino 660 fuel pump instead of replacing it?
  • A: Cleaning is generally not considered a viable solution for a failing pump. While you can clean the external strainer sock, the pump motor itself cannot be effectively cleaned or repaired by owners. Debris causing internal damage or bearing/motor wear necessitates replacement. If the strainer is clogged but the pump still works, cleaning the strainer might help temporarily, but if the pump was starved or overheated due to the restriction, its lifespan may already be compromised.
• Q: How long should a Yamaha Rhino 660 fuel pump last?
  • A: There's no fixed lifespan as it depends heavily on fuel quality, filter maintenance, running habits, and environmental conditions. With excellent maintenance and clean fuel, 7-10 years or several thousand hours of operation is achievable. Neglecting filters or using poor fuel can lead to failure much sooner. Many pumps fail between 5-10 years of typical recreational use.
• Q: How much does a Yamaha Rhino 660 fuel pump cost?
  • A: Prices vary significantly:
    • OEM: Expect $150-$300+ USD for the genuine Yamaha assembly.
    • Quality Aftermarket: $70-$150 USD is common for reputable brands.
    • Cheap Aftermarket/Budget Brands: $40-$70 USD, but these carry higher failure risk.
      (Note: Prices are estimates subject to change; shop around).
• Q: Does a Yamaha Rhino 660 have a fuel pump relay?
  • A: Yes. A relay controls the power circuit to the fuel pump, switching the high current load based on signals from the ECU and ignition switch. It's located in the fuse box. A faulty relay is a common cause of "no power to pump" issues.
• Q: Where is the Yamaha Rhino 660 fuel filter? Is it separate from the pump?
  • A: Yes. The Rhino typically has an external in-line fuel filter located somewhere between the fuel tank outlet and the engine's fuel rail. It is a separate serviceable component distinct from the pump's internal strainer. Consult your manual/service guide for exact location (often near the rear frame rail or firewall). Replace this filter regularly! The pump assembly inside the tank also has an inlet strainer/sock attached directly to the pump intake.
• Q: What fuel pressure should a Yamaha Rhino 660 have?
  • A: Specifications can vary slightly by year, but generally, the fuel pressure should be between 36-38 PSI (pounds per square inch) at idle. Always consult a specific service manual for the exact specification for your model year, but stable pressure around 36 PSI at idle is typical. Pressure needs to remain stable under load and hold reasonably after shutdown.
• Q: How much time does it take to replace a Yamaha Rhino 660 fuel pump?
  • A: For a reasonably experienced DIYer with the right tools (especially the lock ring tool), allowing 2-4 hours is common. This includes preparation, drain time, reassembly, and initial checks. Add extra time if it's your first attempt or if fasteners are rusty/stuck.

Final Considerations & Decision Making

A failing Yamaha Rhino 660 fuel pump will inevitably lead to operational problems, ranging from inconvenient to potentially dangerous if it fails completely during use. Accurate diagnosis using the methods outlined is crucial before investing in a replacement. Understand the symptoms, systematically test electrical power at the pump connector, and most definitively, perform a fuel pressure test. Quality replacement parts (OEM or reputable aftermarket) and careful installation are key to restoring reliable performance.

While the replacement process requires moderate mechanical skill, access to the pump via the bed floor panel makes it significantly more accessible than designs requiring full tank removal. Following the step-by-step guide prioritizing safety will lead most owners to successful DIY repair. For those uncomfortable with the electrical testing, fuel system safety, or the installation complexity, seeking professional service is a wise choice.

Implementing proactive maintenance practices – regular fuel filter changes, using clean fuel conscientiously, and proper storage techniques – is the single best investment to maximize the longevity and trouble-free operation of your Yamaha Rhino 660's fuel delivery system. A healthy fuel pump ensures your Rhino starts easily, runs smoothly, and delivers the power you expect when exploring the trails. Understanding, diagnosing, and addressing this critical component is fundamental to reliable Rhino ownership.