Yamaha F150 - Alarm & Shutdown - Shift Position Switch?

[Dapman04]

Good morning.....I'm having an issue with one of my 2004 Yamaha F150's. I took the boat out yesterday for a 20 minute no wake cruise and noticed that the port engine seemed to be running at a lower RPM than the starboard. We got to our picnic area and stayed for a half hour or so - go to leave and literally three minutes in to the return trip home an alarm goes off and the port engine shuts off. I tried to restart it but it just cranks. When I got home, I ran the YDS scan and it is showing a code 28 shift position sensor code. From what I've read this is usually from shutting the engine down while in gear - which I likely did in panic of the alarm. Can anyone tell me what the symptoms usually are if this switch is truly bad? I'm leaning more to a fuel issue but don't want to ignore the possibility that it's a sensor. I had some trouble with the other engine recently and sent the injectors out to be cleaned and tested and it seems to run fine now. I appreciate your help and insight!

[TownsendsFJR1300]

What were your RPM's when the engine died?

[Dapman04]

RPMs were right around 1,000-1,100

[TownsendsFJR1300]

It shouldn't pop a code turning off in gear.. I gather the lanyard clip IS in place? If not in place it will crank and NOT start(kills ignition)

Under the hood, where the cables attach, (and the shift / throttle slide are, all should be aligned. There is a neutral switch (not the correct terminology)
there as well, you'll see the two wires.

I would check that their aligned. There's an alignment mark which everything should line up in neutral.

I would next check for spark while cranking (remove spark plug, ground to head and crank).

I would tend to think you have a fueling issue as well especially if your pulling from the same fuel tank that clogged up the injectors on the other engines.

But the alarm going off, IDK. Someone else will chime in.

[Dapman04]

Thanks for the detailed reply - I will check the alignment as soon as it stops raining here

thank you!

[rodbolt17]

nope.
no alarms nor sensor failures that will shut off the engine.
time for basic testing.
do you have spark?
do you have rail pressure?
are the cam timing marks agreeing with the flywheel marks?
simple stuff first.

[rodbolt17]

I reread the lead post, for clarity. did the port engine alarm and then shut down?
did it alarm and YOU shut it down?
that engine system does have a stall alarm that will alert the operator of an unplanned engine stoppage.
IF the ECU "sees" no shut down signal and "see's the engine is no longer running it alarms to alert the operator that the engine has stalled.

[Dapman04]

Honestly I don't remember - heard the alarm and noticed the RPMs dropping. I'm sure it would have shut off it I didn't do it first. I wasn't aware of the stall alarm - if it wasn't getting the right fuel pressure (clogged vst, dirty injectors, etc.) could the engine shut down and I get this alarm?

As a side note, I just went down to boat and it started just fine. The weather isn't conducive to taking it out though so I have no idea how it would act in gear.

[rodbolt17]

if for any reason that motor shuts off without the STOP signal(grounding the white wire) it alarms.
doesn't matter if the thing ran out of gas.
doesn't matter if it is an improper ISC valve adjustment. all the ECU "sees" is that the engine is no longer running and it did not get a shut down signal from the helm.
but other than the emergency stop or ign switch there are no switchs or sensors that will shut the motor off.

[TownsendsFJR1300]

Any updates?