My Yamaha Grizzly 600 Won't Rev


Yamaha first began manufacturing the Grizzly ATV, a large and powerful utility quad, in 1998 with a 600cc model. Since that time, the make has seen numerous engineering spin-offs, including a new 700cc version in 2011. 2001, however, was the make's final year in a 600cc version. For these older ATVs, problems can arise that require minor repairs and troubleshooting. For Grizzly 600 quads that will no longer rev or start, Yamaha mentions two potential problems and solutions in the ATV's owner's manual.

Things You'll Need

  • Standard wrench
  • Pliers
  • 20A fuse
  • Spark plug wrench
  • Spark plug gap tool
  • NGK DPR8EA spark plug

Main Fuse

  • Check the main fuse first. If it has blown, the starter motor cannot work and the quad will not rev.

  • Remove the Grizzly 600's seat. Use a wrench to unscrew the seat and pull it away. The main fuse is located underneath this seat.

  • Use pliers to carefully remove the main fuse.

  • Inspect the fuse. If the connection at the center of the fuse is obviously broken, the fuse is blown. If it is not clear whether the connection has broken, connect the fuse to a multimeter. If the multimeter reads anything other than about zero ohms, the fuse has blown.

  • Replace a blown fuse with a new 20A fuse.

  • Reinstall the seat and operate the electric starter. If the quad still won't start, move on to the next section.

Spark Plug

  • Check the condition of the spark plug if the Grizzly's engine turns over but won't start.

  • Remove the spark plug, located inside the Grizzly's single cylinder. Remove the spark plug cap and use a spark plug wrench to twist the plug counterclockwise and lift it from the cylinder.

  • Inspect the condition of the spark plug. If it is burnt, brittle or cracked, replace it with a new NGK DPR8EA spark plug.

  • Measure the spark plug gap, which is the distance between the hook at the end of the plug. It should measure between 0.03 and 0.04 inch.

  • Elongate the spark plug gap using a spark plug gap tool to gently pull the hook wider if the gap is too thin.

  • Shorten the spark plug gap simply by pressing the hook end against a firm, flat surface.

  • Reinstall the spark plug by turning it clockwise into the cylinder with a spark plug wrench and returning the spark plug cap.

  • Try the electric starter again. If the Grizzly still won't rev or start, take it to the shop for inspection.

Tips & Warnings

  • Yamaha recommends that owners take the Grizzly 600 to a certified Yamaha dealer for major repairs, or to recharge the battery.
  • Only use the parts specified in the Yamaha owner's manual, including a 20A fuse and a NGK DPR8EA spark plug. Using any non-certified parts can result in serious engine damage.

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  • Photo Credit fuse image by Alison Bowden from
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