no power on the engine side - still wonder how the tach reading rpms ? and you are showing even oil pressure - coolant temp - voltage and so on as mentioned in your post ---- all gauges reading. . . .

thought about this and without a wiring diagram in hand nor your engine --- my only thoughts on the logical side is the starter relay went bad or lost its connection and or the 20 amp fuse for the starter blew. Or both ?

The engine has a hot stud that uses 2 battery positive cables - one from battery to hot stud and hot stud to the starter. if any of that lost power the gauges would not be working. BUT WILL add. There is a 90 amp fuse at the starter as well..... Depending --- I can see if the 90 amp fuse at the starter blew causing a no start but still have power at the gauges . Possible 90 amp fuse at the starter ? I have to rethink that one. Its late.

I have a 2011 8.2 HO and experienced this exact problem. After putting on the G3 computer, and showed no issue. We found a loose term. to the starter. not very loose, maybe just enough though. I to was cruising along and engine just died like I shut the key off. Checked all the common things like kill switch, batteries, etc. I have analog gauges so it did not read like your's. Temp, oil press, volts, fuel all fine. Would not start right up. 24 hrs later ran like it always has?? Hoping that the loose wire was it!! Good Luck

that was my point completely lost engine power - and all at the dash still works ?

there needs to be questions answered as to the gauges - when power is turn off do all gauges go off as well or do they stay stuck ??

turn key on what exactly do all the gauges do ? for instance the tach is showing 0 or 2000 rpms ? whats voltage reading ?

What kind of gauges are these ?

Smartcraft gauges ?

IS THIS A DTS APP or mechanical throttle and shift ??

Also the 90 amp fuse might be on the hot stud / engine side rather than starter. They were moved it for a couple of reasons. One is to stay dryer. I can see if this was cabled wrong by dealer or boat manu - if the 90 amp fuse went out being the issue.

possible loose cable - pwr or ground connection knocked out 20 amp starter fuse.

that 20 amp starter fuse is more than just for the starter -- If you lost trim as well - this would be the issue for the no start - the engine dying while driving and starter not working. The 20 amp is for like 6 things. Now I have to remember what I want to say for supplies 12 V to the fuel pump relay ???? - The 20 amp fuse ??

The 8.2 have only digital output for gauges! Analog gauges did not work on this engines,only with an extra interface.
So i am shure he use scmartcarft gauges!
Michael

I was not talking about the signal for the gauges - I was asking what readings at the gauge and brand of gauges, plus there is other players making gauges for digital signals besides smart craft (Merc)

he can have vessel view as well as well

Matter of fact most marine gauges makers are doing gauges for digital signals., faria, V three, Livorsi, Medallian, BeBe, and so on

I needed a Merc. interface "go between" to make my analog gauges work with my engine. I used my boat for twice the time I had when I had the problem. No issue. I would feel more reassured if I knew exactly what the problem was.

Engine does not have digital throttle - does have analog reading gauges.
ALL gauges stay in the same position as when the engine was running even when turning the key off - run or start ..... all circuit breakers ok, two 40 amp breakers near dash ok. I did not see any breakers on engine
when shut down happened. Also, nothing works that requires the key to be in the "on/run" position to function.
The boat is at the dealer now.... we will see what they find, soon I hope.
Thanks for all the replies.

thanks for the update. Keep in mind the TACH works off the crank position sensor BAD crank sensor causes a no start issue but the starter to NOT turn over is another issue.

I would not rule out the crank sensor either here.

I understand your gauge set up - its set up thru the interface that is needed for digital signals to analog. With that said other areas need to be checked.

The interface, the PCM and the crank position sensor. IMO all need to be checked out very closely.

For ME this is the most interesting issue posted I have seen up here in a while. All Follow ups on your end would be appreciated . I am closely following this post and of course if it turns into a lunch eater for whomever, I would like to get a shot at fixing it even being many miles away.