Yamaha Rhino 660 Starting Problems

The Yamaha Rhino 660 is a tough UTV, but starting problems can leave you stranded and frustrated. Owners often encounter issues ranging from a dead starter to fuel delivery quirks. Knowing what to check and how to troubleshoot saves time and money. Here’s a practical guide to the most common starting problems on the Rhino 660, what causes them, and how to fix them for good.

Weak or Dead Battery

The number one cause of starting problems with the Yamaha Rhino 660 is a weak or dead battery. Even a slightly undercharged battery can cause sluggish cranking or make the Rhino click but not turn over. This UTV requires a strong battery, especially in cold weather. If the starter struggles or you hear rapid clicking, test the battery voltage with a multimeter. Healthy batteries should show 12.6 volts or more at rest. Anything below 12.2 volts means the battery is likely discharged or dying.

Check the battery terminals for corrosion or loose connections, which can interrupt current flow. Clean terminals with a wire brush and ensure they’re tight. If the battery is over three years old or no longer holds a charge, replace it with a quality AGM or lead-acid unit rated for the Rhino 660. Don’t overlook grounding wires leading from the battery to the frame - a poor ground can mimic battery failure and create intermittent starting issues.

Starter Motor Failures and Solenoid Issues

If the battery checks out but the engine won’t turn over, the starter motor or solenoid could be the culprit. The Yamaha Rhino 660 starter can wear out, especially in machines used for mudding or water crossings. Symptoms include a single click with no crank, or a grinding noise. Sometimes hitting the starter lightly with a tool can temporarily free up stuck brushes, confirming the motor is at fault.

The starter solenoid acts as a relay and can fail internally. Listen for a solid click from the solenoid near the battery when you turn the key. If you hear nothing, check for voltage at the solenoid’s small trigger wire while turning the key. If there’s voltage but the solenoid doesn’t click, it probably needs replacement. Accessing the starter on the Rhino 660 is straightforward but may require removing some body panels. Always disconnect the battery before working on starter circuits.

Fuel Delivery and Carburetor Troubles

No fuel, no start. The Rhino 660 uses a carbureted 660cc engine, so fuel delivery problems are common, especially if the machine sits for weeks or months. Old gasoline gums up jets and float bowls, preventing starting. If the engine cranks strong but doesn’t fire, remove the airbox cover and spray a little starting fluid into the carb throat. If the engine fires briefly, suspect fuel delivery issues.

Check the fuel shutoff valve (petcock) for blockages and make sure it’s in the ON or RESERVE position. Fuel filters in the tank or along the fuel line can clog with debris or varnish. Replace any old fuel lines that look cracked or brittle. If you’re still having trouble, remove the carburetor, clean all jets and passages with carb cleaner, and inspect the float needle for sticking. Keeping fuel fresh and running the engine regularly is the best prevention.

Ignition Switch and Electrical Connections

Sometimes, a starting problem isn’t mechanical but lies in the Rhino’s wiring. The ignition switch can wear out over time, failing to send power to the starter circuit. If turning the key gives no response whatsoever - no lights, no clicks, nothing - check that the switch is functioning. You can test this by jumping the starter solenoid terminals with a screwdriver (in neutral, with the brake on). If the engine spins, the ignition switch or its wiring is likely bad.

Rodents occasionally chew wiring harnesses, and connectors can corrode. Inspect the main harness under the hood and under seat for green or white corrosion in connectors. Spraying these with contact cleaner and applying dielectric grease helps prevent future issues. Pay close attention to the large grey connector near the battery and fuse block. Even a loose connection here will stop the Rhino from starting.

Neutral and Brake Switch Interlocks

The Rhino 660 has safety interlocks requiring the shifter to be in neutral and the brake pedal pressed before the starter will engage. If the starter does nothing when you turn the key, double-check that you’re in neutral. The neutral safety switch can fail or get knocked out of alignment, especially after hard off-road use. If the neutral light doesn’t come on with the key, this switch may be at fault.

You can test the neutral switch by unplugging it and jumping the terminals with a short wire; if the starter now works, replace or adjust the switch. The brake pedal switch can also fail or stick. Wiggle the pedal as you try to start, and listen for a faint click from the relay. Clean or replace the switch if needed. These small interlocks are easy to overlook but are frequent sources of no-start complaints.

Bad Spark Plug or Ignition Coil

If the engine cranks but never fires, spark can be the missing ingredient. Remove the spark plug, reconnect it to the coil wire, and ground the threads to the engine block. Crank the engine while watching for a bright blue spark at the plug tip. A weak or absent spark points to a fouled plug, bad ignition coil, or a problem with the CDI box.

The Rhino 660 is sensitive to plug condition. Replace the spark plug every season, using the correct NGK DPR8EA-9 or equivalent. Inspect the coil wire for cracks and ensure it’s firmly attached at both ends. If you’re not getting spark but the plug is new and the coil checks out, the CDI (ignition control box) may be failing - this is rare, but possible, especially if the Rhino has been submerged or the wiring is in poor shape.

Intake and Exhaust Blockages

It’s less common, but blocked air intakes or exhausts can cause starting issues. Mud, rodents, or debris can clog the air filter housing or the intake boot, starving the engine of air. A severely clogged filter makes the engine hard to start and can cause it to flood. Remove the air filter and inspect for mud or mouse nests. Replace or clean the filter regularly, especially after riding in dusty or wet conditions.

The exhaust can also get blocked, particularly if the Rhino has been parked where rodents are present. A nest or mud wasp plug in the muffler can create enough backpressure to prevent starting. Remove the muffler or look into the tailpipe with a light to check for obstructions. Keeping the intake and exhaust clear is simple but often overlooked maintenance that prevents stubborn no-start symptoms.

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