Yamaha Rhino 660 Starting Problems

The Yamaha Rhino 660, a workhorse of the UTV world, is known for its reliability and ruggedness. But even the toughest machines can sometimes refuse to cooperate, leaving you stranded with a frustrating starting problem. Diagnosing and fixing these issues can seem daunting, but with a systematic approach and a little know-how, you can often get your Rhino roaring back to life.

First Things First: The Obvious (But Often Overlooked) Checks

Before diving into complex troubleshooting, let's cover the basics. You'd be surprised how often a simple oversight is the culprit.

Fuel Level: It sounds silly, but ensure you actually have enough gas in the tank. The fuel gauge can be inaccurate, especially on older models.
Fuel Valve: Make sure the fuel valve (usually located near the fuel tank) is in the "ON" position. Sometimes it gets bumped to "OFF" accidentally.
Battery Connections: Check the battery terminals for corrosion. Clean them thoroughly with a wire brush and baking soda solution if necessary. Ensure the connections are tight. Loose or corroded connections can prevent the starter from getting enough power.
Kill Switch: Double-check that the kill switch (usually a red switch on the handlebar) is in the "RUN" position. It's easy to accidentally hit this switch.
Parking Brake: The Rhino 660 often requires the parking brake to be engaged for starting, especially if the transmission is in gear. Ensure the parking brake is fully engaged.
Fuses: Locate the fuse box (usually under the seat or near the battery) and inspect the fuses. Look for any blown fuses and replace them with the correct amperage rating. A blown fuse can disable critical starting components.

If all these simple checks pass, it's time to dig a little deeper.

Battery Blues: Is Your Battery Holding a Charge?

The battery is the heart of the starting system. A weak or dead battery is a common cause of starting problems.

Testing the Battery: Use a voltmeter to check the battery voltage. A fully charged 12-volt battery should read around 12.6 volts. A reading below 12 volts indicates a discharged battery.
Charging the Battery: Use a battery charger to fully charge the battery. Follow the charger's instructions carefully.
Load Testing: After charging, perform a load test on the battery. This test simulates the drain of the starter motor and reveals if the battery can hold a charge under load. Most auto parts stores offer free battery load testing. If the battery fails the load test, it needs to be replaced.
Battery Age: Batteries have a limited lifespan. If your battery is several years old, it may be time for a replacement, even if it seems to hold a charge.

Fuel System Foibles: Getting Gas to the Engine

If the battery is strong, the next area to investigate is the fuel system. The engine needs fuel to run, and a blockage or malfunction in the fuel system can prevent it from starting.

Fuel Pump: The fuel pump is responsible for delivering fuel from the tank to the carburetor. If the fuel pump is failing, it may not be providing enough fuel to start the engine.
- Testing the Fuel Pump: Disconnect the fuel line at the carburetor and crank the engine. Fuel should be flowing from the fuel line. If no fuel is flowing, the fuel pump may be faulty.
- Fuel Pump Relay: The fuel pump is controlled by a relay. A faulty relay can prevent the fuel pump from operating. Locate the fuel pump relay (consult your Rhino's service manual) and test it with a multimeter.
Carburetor: The carburetor mixes air and fuel to create a combustible mixture. A dirty or clogged carburetor can prevent the engine from starting.
- Cleaning the Carburetor: Remove the carburetor and disassemble it carefully. Clean all the jets and passages with carburetor cleaner. Use compressed air to blow out any remaining debris. Reassemble the carburetor and reinstall it.
- Pilot Jet: The pilot jet is responsible for supplying fuel at idle and low speeds. This jet is particularly prone to clogging. Ensure it is clean and clear.
- Float Level: The float level in the carburetor must be set correctly. If the float level is too high or too low, it can cause starting problems. Consult your Rhino's service manual for the correct float level setting.
Fuel Filter: A clogged fuel filter can restrict fuel flow to the carburetor. Replace the fuel filter regularly to prevent this problem.

Ignition Issues: Spark, Spark, Where Art Thou?

The ignition system provides the spark needed to ignite the air-fuel mixture in the cylinder. A problem with the ignition system can prevent the engine from starting.

Spark Plug: The spark plug ignites the air-fuel mixture. A fouled or worn spark plug can prevent the engine from starting.
- Checking the Spark Plug: Remove the spark plug and inspect it. Look for signs of fouling, such as carbon buildup or oil deposits. Clean the spark plug with a wire brush or replace it with a new one.
- Testing for Spark: Reconnect the spark plug to the spark plug wire and ground the spark plug against the engine. Crank the engine and observe the spark plug. You should see a strong, blue spark. If there is no spark or the spark is weak and yellow, there is a problem with the ignition system.
Ignition Coil: The ignition coil amplifies the battery voltage to create the high voltage needed for the spark plug. A faulty ignition coil can prevent the engine from starting.
- Testing the Ignition Coil: Use a multimeter to test the resistance of the ignition coil. Consult your Rhino's service manual for the correct resistance values. If the ignition coil does not meet the specifications, it needs to be replaced.
CDI Unit (Capacitor Discharge Ignition): The CDI unit controls the timing and duration of the spark. A faulty CDI unit can prevent the engine from starting.
- Testing the CDI Unit: Testing a CDI unit typically requires specialized equipment. It's often best to consult a qualified mechanic to diagnose a CDI unit problem.
Stator: The stator generates the electrical power needed to charge the battery and power the ignition system. A faulty stator can prevent the engine from starting.
- Testing the Stator: Use a multimeter to test the output voltage of the stator. Consult your Rhino's service manual for the correct voltage values. If the stator does not meet the specifications, it needs to be replaced.

Compression Concerns: The Squeeze is On!

Compression is essential for the engine to run. Without adequate compression, the air-fuel mixture cannot be properly ignited.

Compression Test: Perform a compression test to check the engine's compression. Remove the spark plug and screw a compression tester into the spark plug hole. Crank the engine and observe the compression reading. Consult your Rhino's service manual for the correct compression value. Low compression can indicate worn piston rings, damaged valves, or a blown head gasket.
Valve Adjustment: Incorrect valve clearance can cause low compression. Check the valve clearance and adjust it according to your Rhino's service manual.

Electrical Gremlins: Chasing Down Shorts and Opens

Electrical problems can be tricky to diagnose, but a systematic approach can help.

Wiring Harness: Inspect the wiring harness for any damaged or frayed wires. Repair any damaged wires with electrical tape or heat shrink tubing.
Connectors: Check all the electrical connectors for corrosion or loose connections. Clean the connectors with electrical contact cleaner.
Grounds: Ensure all the ground connections are clean and tight. A poor ground connection can cause a variety of electrical problems.

Frequently Asked Questions

Why does my Rhino crank but not start? This could be due to a lack of fuel, spark, or compression. Check the fuel pump, spark plug, and perform a compression test.
Why does my Rhino start and then die? This is often caused by a dirty carburetor, a faulty fuel pump, or a vacuum leak. Clean the carburetor and check the fuel pump pressure.
What does a bad CDI box do? A bad CDI box can cause a no-spark condition, intermittent starting problems, or engine misfires.
How do I clean my Rhino's carburetor? Disassemble the carburetor and clean all the jets and passages with carburetor cleaner and compressed air.
How often should I change my Rhino's spark plug? Check your owner's manual, but generally, it's recommended to replace the spark plug every 100 hours of operation.

Conclusion

Troubleshooting starting problems on your Yamaha Rhino 660 can be a challenge, but by following a methodical approach and systematically checking each component, you can often identify and fix the issue yourself. Remember to consult your Rhino's service manual for specific instructions and specifications. With a little patience and persistence, you'll be back on the trail in no time!