F115TXRD 2005 surging

[99yam40]

Out on lake right now first thing this morning launch boat ran wide-open at 5800 RPM for 10 minutes turned around on the lake was heading back to the dock all of a sudden it kicked out put a fuel gauge on it under load maintaining 42 psi and when the engine kicks out it definitely loses fuel pressure but it’s electrical like it it’s not kicking out as an a lost fuel pressure

sounds like you are saying it is losing spark and not fuel, is that correct?

[MattF115]

I wish I could say that I got a video of what it is doing trying to upload but having a problem doing that. It’s like someone hit the key to shut it off but then turns back on.

[TONYG279]

my 2018 F90LB had some kind of a similar problem, surging under speed, then it was good for a while, and then it started doing it again. Then after that very rough at idle ( something that was not happening at the beginning of the surge problem) to make a long story short, only 2 cylinders were working because two Spark Plugs were bad, they look fine just by looking at them but they were bad, some people dont even change spark plugs every year and dont run into any problems, well i had not one but two bad sparkplugs, and these were the ones that came factory with the engine. So i guess you could try that.

[MattF115]

I have changed the plugs already as it was the easiest thing to do. Runs and idles great.

[99yam40]

I wish I could say that I got a video of what it is doing trying to upload but having a problem doing that. It’s like someone hit the key to shut it off but then turns back on.

I thought I aleady replyed to this but do not see mine, so.
clean all battery connections, both + and -., all ends of cables, maybe a bad connection loosing power to ECU

[MattF115]

I cleaned the battery and charged it up as well i unplugged ECU when i was on lake that did not change anything

[MattF115]

Is there values for metering the coils and stator maybe i can start looking for that as it seems to get worse with heat when i first put it in the water it ran at 5800rpm for 10 min then when i slowed down and turned around and started going again it started to crap out.

[fairdeal]

heading back to the dock all of a sudden it kicked out put a fuel gauge on it under load maintaining 42 psi and when the engine kicks out it definitely loses fuel pressure but its electrical like it its not kicking out as an a lost fuel pressure

if the engine stalls dead, the ECM would stop running the high pressure pump,
but if the crankshaft is turning, the pump should be continuously running
and rail pressure should be constant

Is there values for metering the coils and stator maybe i can start looking for that

you can ignore the "stator"
on an EFI 4-stroke all that does is keep the battery from discharging

[MattF115]

So when it kicks out fuel pressure does not fall off past 40psi but this all happens in a milsecond. What tells the coil to fire would that be part of the stator or is there a crank sensor.

[MattF115]

Can anyone tell me what #5 relay controls boat ele.PNG