For all the unexplained shutdown issues

[joe_db]

We seem to have a lot of these threads.
I was hoping maybe we could get a sticky for people to reference.
Here is my take:
No one likes to part with a dollar they don't have to and we all know copper wire was invented when 2 sailors saw a penny on the ground at the same time
That said, ruined cruises, towing charges, and endless part swapping adds up. You can swap about *everything* in the entire boat and still not fix your issue if you have no tools to determine what is shutting you down. Absent instruments, you are guessing.
I'll lead off with this:

https://moyermarine.com/product/the-engine-warning-and-diagnostic-system-ktas_01_564/

[ndutton]

Well said Joe. I recently made a post that it seems the majority of problems come from systems external to the actual engine, fuel and electrical for example, exactly what the EWDS monitors.

I consider myself a pretty good troubleshooter but I still have the EWDS on constant sentinel duty figuring when a shutdown happens I can benefit from the information it provides. That is, make my troubleshooting easier and quicker. However, through diligent and aggressive maintenance the goal is to never have an EWDS alert. Buy it, install it and then do your best so that it is never called upon but when it is . . . like insurance, y'know?

[joe_db]

Part II:
I have both fuel pressure and fuel filter vacuum gauges. The fuel pressure is visible from the cockpit.
Without these gauges I would have *never* figured out a couple of hugely frustrating fuel issues that both mimicked coil failures.
1. I had debris in the tank that would get sucked onto the pickup tube, but then fall back off.
2. At one time with my engine running at 180 degrees I would have what seems like vapor lock with intermittent pressure drops and then pressure drop to 0. It too would cure itself from sitting.

These instruments in total won't pay for an hour or maybe two of towing at going rates.
I don't have the EWS myself because I was too far along with my own DIY version when it came out, but I sure would get one if starting from scratch.

[Peter]

Does the EWDS tell you which sensor tripped first?

Thanks,

Peter

[ndutton]

Does the EWDS tell you which sensor tripped first?

No.

Please appreciate that during the development of the EWDS and the many decisions along the way, affordability was paramount. Earlier, more elaborate prototypes would have cost thousands but a value judgement had to be made so many bells and whistles were nixxed. We always recommended positioning the display in view of the helm so the indicator light array can be observed as soon as the buzzer launches.

Upon shutdown or nearly so, systems affected but not the primary cause take a little more time to cross their respective trip points. For example, let's say the OPSS fails. The engine will shut down once the fuel in the carb bowl is expended and when shut down occurs, oil pressure will drop to zero as will the raw water flow. Eventually three EWDS lights will illuminate, Fuel (amber), Oil (blue) and Flow (green) but fuel will have illuminated well before the others as soon as the fuel pressure dropped below 1 PSI. A buzzer alert is ALWAYS accompanied by one or more warning lights.

Also, lights that don't illuminate can tell as much as the one(s) that do. Another example: assume the engine shuts down due to an overheated coil (shame on you for not studying the 5 star Coil Input Information thread). Coil temperature is not a monitored parameter for the EWDS so shut down occurs without a warning buzzer or any indicator lights. With the engine stopped, oil pressure falls (blue light + buzzer), fuel pressure falls (amber light), raw water flow stops (green light) but none of these were lit at the time of actual shut down. Whatever the problem was that caused the shut down it wasn't the fuel delivery, wasn't oil pressure, wasn't poor ignition system voltage, wasn't overheating or loss of water flow. Those are immediately off the table so you can focus your attention elsewhere. Knowing what it's not is an important step to knowing what it is.