How to Troubleshoot a Yamaha 350 Warrior

by Brianna Collins

Yamaha first introduced the Warrior 350 make of racing quad in 1987, the first ATV with an electric starter in the world and one of the company's top-selling sport ATVs. It lasted almost 20 years, with its final production year in 2004. Despite rigid quality controls, it -- like any recreational vehicle -- can experience mechanical problems that prevent the quad from starting or running. For minor repairs and troubleshooting, Yamaha lays out a number of specific steps that owners should take regarding the battery, compression, ignition, and fuel cock.


Use the electric starter to determine whether or not the battery is faulty.

Listen to the engine turn over. The battery is working properly if turn over is quick. If the engine turns over slowly or not at all, the battery may be dead.

Recharge the battery.

Check the battery's connections and fluid levels, as this may also cause the engine to turn over slowly.

Replace the battery if connections are loose or fluid levels are low.


Use the electric starter again, this time checking for compression.

Move on to the ignition system check if there is compression.

Take the quad to a Yamaha dealer to inspect this system if there is little or no compression.


Remove the spark plug and inspect the electrodes to check the ignition system. Clean with a dry cloth if the area is wet.

Attach the plug cap and ground it to the chassis.

Use the electric starter. If the spark is good, the ignition is working properly.

Ensure that the plug gap is set between 0.02 and 0.03 inches if the spark is weak.

Try the starter again. Replace the spark plug if the spark is still weak.

Take the Warrior 350 to a Yamaha dealer for inspection if the spark is weak or if there is no spark, as more serious repairs may be required.

Fuel System

Check to see if there is fuel in the tank. If there is no fuel, refill and attempt to start the engine again.

Turn the fuel cock to "RES" and try to restart the engine if there is a small amount of fuel.

Turn the fuel cock off if there is an adequate fuel level. Remove the fuel hose and turn the fuel cock back on.

Check the flow of fuel. If it is not coming through, then the fuel cock may be clogged. Clean the fuel cock thoroughly and attempt to start the engine again.


  • check It is possible that all of these systems are working properly, but the Warrior 350 is still not running or starting. In these instances, more serious repairs are likely required. Yamaha recommends taking the Warrior to a qualified dealer for repairs, as they have the specific tools and training to handle more serious repairs.


  • close While handling fuel and working on the fuel system, do not smoke or have an open flame nearby. This can cause the fumes to explode.
  • close Always wear gloves and eye protection when handling batteries and battery fluid to avoid battery acid burns.

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About the Author

Brianna has been writing professionally since 2009. She has a Bachelor of Fine Arts degree and is excited to be part of a community that contributes to the free sharing of information and ideas.

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Photo Credits

  • photo_camera gasoline warning image by Albert Lozano from