Chattering Low Voltage Alarm 6CTA8.3

[Rick Thompson]

I have 6CTA8.3 engines in my trawler. The starboard engine has an intermittent low voltage fault, it “chatters” – goes on and off so fast that the buzzer just barely makes a noise, more of a clicking sound and the alarm light flickers. The voltage reading on the panel shows more that 24V usually around 26V even while chattering.

On my last long trip, the chattering seemed to my stabilizers to cut off (3 times) and finally it caused the engine to shut down. Once I restarted the engine, the chattering stopped.

Any recommendations.

Topic

[Corey Schmidt]

Rick Thompson wrote:

Okay, I understand. I found a somewhat loose connection on the black side of the starter (about 1/2 turn). The wires could move but not freely. I took the boat out for a one hour test run yesterday. No chattering and no problems discovered. I really hate intermittent problems. I will take your advise and continue to isolate the problem.

Thanks for your help and info. What does that circuit breaker do on the newer engines? Could the connector I found with silicon in the fitting be for it?
One more question, my parts catalog shows the analog heat gauge as 3915605 but I can’t seem to find it when I search for parts? Is there another number? Do you have any in stock, if so, what is the cost?

Send me a picture of the connector with the silicone… probably the alternator feedback diode:

Cummins Marine Replacement Diode

Re: the heat gauge 3915605… I couldn’t find anything for that part number… it came up invalid so not sure?

[Corey Schmidt]

Only way to really troubleshoot something like this is to minimize the simplify the DC distribution to where everything works 100% as expected… and then continue to make connections until the problem re-occurs and/or is eliminated.

[Rick Thompson]

My engine is a 1999 model. There is not breaker in the position shown in the photo. Under the lifting point, near the oil cooler for the gearbox, there are several wiring harness connections, all are still tight. There is one darker grey connector that is filled with silicon. Not done by me, I just noticed it for the first time.

[Rob Schepis]

Engine Mounted Circuit Breaker

Have you checked this breaker? that’s were power for your instruments/ignition leaves the engine room…

https://www.sbmar.com/community/topic/6cta-circuit-breaker/

[Rick Thompson]

Since the chattering is only on the starboard engine, I checked all of the 24V connections from start batteries to the common point (the engine cutoff switch for both engines) and from there to the 24V alternator (port side engine) via the port starter. I then checked connections from the cutoff switch to the starboard engine and the PH panel. I will complete the check at the flybridge panel today.

BTW, the starboard engine has a 12V alternator to charge the house bank.

[Corey Schmidt]

Have you gone through the boat to check ALL of the battery connections to make sure that everything is CLEAN and TIGHT?

[Author]

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