Generator cranks but will not start; no error code displayed on Yamaha controller.

Safety first: Turn the generator OFF and disconnect battery negative. Keep flames and sparks away from fuel.

• Confirm fuel valves: Verify that all manual fuel shutoff valves at the tank and generator are fully open.
• Check fuel level: Ensure there is adequate fuel in the tank or sufficient gas supply pressure.
• Inspect and replace fuel filter: Replace the primary fuel filter with a Yamaha-specified element if it is dirty or overdue for service.
• Prime the system: Use the manual priming pump (diesel) or follow Yamaha priming procedure to remove air from the lines.
• Test electric fuel pump: Turn key or controller to RUN (no crank) and listen for pump operation. If silent, check the pump fuse and relay, then replace the fuel pump if it does not run with power applied.