Yamaha 115 four stroke 2005 help!

[Derbyian1983]

Been out today with a friend with the above engine.... Owned the boat for 4 years with no problems at all, now it's started loosing revs! Will rev to 5800rpm. Then backs down to 2500rpm. Recent service 2 weeks ago. Tried new fuel tank with new lines.... Any help or ideas? Thanks in advance!!!

[Turbodiesel]

Have you tried squeezing the primer bulb when the fault happens? If the engine comes back into life, check the fuel pumps (might have 2 pumps on older models)

[Derbyian1983]

Yes tried that and it makes no difference at all. Tried a different fuel tank too. He filled it with tescos fuel when the problem started and used alot of it but since filled it back up with texico and problem is getting worse.

[benc]

I had similar on my 2007 150 hpdi, kept dropping into limp home mode. Stopping the engine and restarting it seemed to sort it for a while. On mine it was bad connection on one of the sensors. Disconnecting and cleaning up sorted it. I think it was one of the oil sensors

[clydeoutboards]

I agree with benc. this sounds like a faulty sensor that is designed to protect your engine not working as it should and putting it into limp home mode. If you get your local dealer to put the computer on it he will have an answer for you in in minutes.

Dave

[Derbyian1983]

Thanks guys! Boats gone into have a diagnostic sometime this week.