Yamaha EFI outboard loses power at speed: fuel supply
Teilen
Applies to: F-series 4-stroke EFI (Yamaha), 2000s on
Symptoms
- Runs at idle, bogs at higher RPM
- Primer bulb collapses
- Engine warning or slow speed limit
Why it happens
A clogged water-separating filter or vapor separator (VST) filter, or a weak low-pressure fuel pump, starves the engine under load.
How to fix it
- Check the primer bulb and fuel line for kinks or collapse.
- Replace the water-separating fuel filter.
- Inspect and clean the VST filter.
- Test fuel pressure against the manual spec.
- Replace the low-pressure pump if pressure is low.
Tools and parts
- Fuel filter
- Fuel pressure gauge
- VST filter
What the factory service manual covers
Fuel system: VST filter, pump tests, fuel pressure spec. The full procedure, specs and wiring diagrams are in the factory service manual for your machine.