Dead in the water - Update
On 5/25 I posted a request for help when our 6BTA-5.9 shut down suddenly. There were a number of very helpful responses along with a request that we post a final resolution.
The shutdown occurred when the engine mounted circuit breaker tripped.
Because the engine is almost 20 years old and the circuit breaker reset button was painted I assumed that it was an original component and ordered a new one from Seaboard Marine.
Installed the new breaker last week and went through the all of the wiring connections in that circuit, cleaning and spraying with Corrosion Block. I did not see a connection that appeared to be suspect but at least I know they are good now.
Over the weekend we took the boat out for several nights anchoring and totaled about 11 hours of run time with no problems.
Hopefully this is one more learning opportunity completed and the problem is resolved!
Thanks again to everyone who offered suggestions.