engine quits

[gettinthere]

After a long day of motoring, when we're at idle speed getting ready to drop anchor, sometimes the main breaker for the engine circuit pops and kills the engine.
I replaced the breaker a year ago but occasionally it still does it.
I can reset the breaker and restart the engine easily.

 

[Benny17441]

As far as I know a diesel engine just needs electricity to power the starter and the control gauges. It does not need electricity as a source of ignition so if the engine is running and there is a power failure it should continue to run as if nothing happened. Are you referring to a malfunctioning shut-off solenoid?

 

[gettinthere]

Perhaps the breaker on the panel works with a stop solenoid?

 

[Nom De Guerre]

Is it a diesel? If it is then maybe it has an electric fuel pump that is shorting out and tripping the breaker, halting fuel flow.

 

[gettinthere]

Yes diesel.
Perkins 4.154 mech pump

 

[sailaway78]

Do you have

Do you have a large alternator, that could possibly be doing something spooky. It may be possible that the alternator could suddenly go to a high enough load to kill the engine at idle.

 

[gettinthere]

100 amp alt that actually puts out no more than 85.
At the end of a long run, batts are typically full or near full so draw would be negligible.

 

[Nom De Guerre]

What is the breaker protecting? Specifically...

 

[DougM]

Fuel filters?.. Fuel pump could be pushing enough fuel at speed to get through a partly clogged filter, but not enough at idle. A slightly clogged secondary filter may be causing the problem. Just a thought

 

[Benny17441]

To trip a breaker you must have a short. You are reporting an intermittent failure so the short comes and goes. Due to the fact that the engine shuts off when the short occurs leads me to believe that a fuel shutoff solenoid is likely involved. I would start by inspecting the wiring harness from the control panel to the engine. These harnesses are usually routed around sharp fiberglass corners and in time and with hull flex the sharp edges the insulation gets chaffed and shorts occur.

 

[gettinthere]

Fuel filters?.. Fuel pump could be pushing enough fuel at speed to get through a partly clogged filter, but not enough at idle. A slightly clogged secondary filter may be causing the problem. Just a thought

Doubtful
The ignition breaker on the main panel trips at the shutdown. Reset the breaker and the buzzer starts and we fire up the engine with no problem.

 

[fredr]

Any alarms that trigger when this happens?
I wonder if it is a low oil pressure that is causing this.

 

[woodster]

just a thought here ...how old is that breaker.....could it be going bad ...i think they are magnetic ...maybe low voltage feeding it at idle...like i said just a thought

 

[Ron20324]

The ignition breaker on the main panel trips at the shutdown. Reset the breaker and the buzzer starts and we fire up the engine with no problem.

An earlier question was, what specifically, circuit flows through that breaker? Not the starter, for sure, maybe the gueages or electric fuel pump?