Engine shut down

i have Cat 3196. Last week I had a salt water leak that sprayed the alternator, 70amp breaker, and starter. After cleaning engine and letting it sit for the week I started them up. Engine seemed to be running fine, but after an hour the engine just shut down. No warning, nothing. My ignigition breaker tripped and battery was to weak to restart. My question is....could the alternator be dead which caused the battery to drain, hence causing my ignition switch to trip to protect the ECM on the engine?

were both engines running? If so the other engines alt. should have been charging batts thru combiner. Maybe bad battery as well.

Sublimetime said:

were both engines running? If so the other engines alt. should have been charging batts thru combiner. Maybe bad battery as well.

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never heard of a combiner? not sure I have one of these. I know I can put the engine batteries in series for an emergency start. I am having alternator bench tested this week.

combiner is usually wired into just before/ near batteries. It takes the charging wire from each altenator and makes it so either alt running charges both battery banks.

Sublimetime said:

combiner is usually wired into just before/ near batteries. It takes the charging wire from each altenator and makes it so either alt running charges both battery banks.

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Ok, so you are talking about the Crossover battery isolator. Yes, I believe it is standard equip on this boat. So I wonder if the isolator was doing its job. Once I have the alternator checked, I will then replace stbd battery and verify everything. I was able to limp home on the one engine. It is always good to practice single engine procedures. This all started due to a drip from my AC manifold then when my forward bilge tried to evac the water, the bilge pump had a crack that I did not notice... It most likely sprayed salt for a couple days on the stbd side. Hence why the alt might be shot. The 70amp fuse for the alternator did not trip, so not sure about that either. I guess I still have some diagnostics to do.

Update...alternator bench tested fine. Now to start finding the gremlin. Grrrr

Aren't these engines mechanical? The only way a Cat mechanical diesel engine will shut down is if power to the fuel solenoid is interrupted (one single wire) or it runs out of fuel. At this point I'd go through the engine's wire harness and battery cables; disconnect and clean all of the terminals and inspect/replace the lugs. Look carefully at the circuit breakers and relays. It is odd that both a circuit breaker tripped and the battery bank went down. As a thought, I believe the alternator's B+ wire is connected to the battery B+ on the starter motor; should either the battery's positive or negative cable become loose or not make good contact the alternator will immediately go very high in voltage, like north of 70 volts, and can damage electrical and electronic components including tripping circuit breakers.

I think we got her going. It looks like the brushes might have been stuck in the alternator, but upon removal and banging around...freed up. Ran engines fine the other week and was charging normally. Thanks all for the input.