- Joined
- Aug 20, 2023
- Messages
- 27
- Reaction score
- 0
- Points
- 1
- Age
- 38
- Model
- Sportsman
2000 Yamaha 115 4 stroke with 375 hours. Meticulously maintained and always ethanol free. I replaced VST, high pressure fuel pump and injectors 4 years ago (~150 hours, boat sat awhile it’s early years). Fuel filters and normal maintenance done yearly. I am having a weird issue that started the end of last season. It would sputter and pumping the bulb seemed to fix it temporarily. I just replaced the anti siphon valve and bulb and now pumping the bulb when the issue occurs does nothing. It did however seem to stay firmer, I do believe the valve was bad. I noticed that if I was ever below 2000 rpm, it would stall or sputter really bad. Any ideas?
UPDATE -
Replaced injectors and spark plugs. Put fuel pressure gauges on fuel rail and read 37 psi when running. Put fuel pressure gauge after low pressure fuel pump and read 10-11 psi when running. It is still stalling. Right before it stalls the gauges stay about the same, maybe go down a few psi. The idle air control valve clicks when I start and then turn off the motor. If the motor stalls, I do not hear the valve click. When it gets ready to stall, I hear it almost gasping for air, like an inhaling for air sound. Ughhhh
UPDATE -
Replaced injectors and spark plugs. Put fuel pressure gauges on fuel rail and read 37 psi when running. Put fuel pressure gauge after low pressure fuel pump and read 10-11 psi when running. It is still stalling. Right before it stalls the gauges stay about the same, maybe go down a few psi. The idle air control valve clicks when I start and then turn off the motor. If the motor stalls, I do not hear the valve click. When it gets ready to stall, I hear it almost gasping for air, like an inhaling for air sound. Ughhhh
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