6BT 5.9 Engine Stalling

[Joe Faith]

I have a 210 hp Cummins 6BT 5.9 engine in my boat. For a couple days this past summer, I heard a slight rev from the engine a couple times. Then it revved up hard and came down but kept running. A short time later, it revved up hard and quit. I turned the key switch and could not get the engine to turn over or make any sound. I changed the racor. But turning the key resulted in no sound such as starter solenoid clicking or buzzing from the key switch. After about 10 minutes, I turned the key switch and it buzzed. The engine then started. I idled toward the harbor miles away.

At the harbor, I changed the fuel filter and had a mechanic look at it. The mechanic tightened a couple studs bolts on the fuel injection pump. But when I tried to go fishing, after about an hour running at 1800 rpms, the engine revved hard. I threw the gear in neutral and throttled way back. I turned the key switch and no sound. After about 10 minutes, I turned the key switch and it buzzed. I started the engine and idled back to the harbor.

I then changed out the key switch and removed the middle section of the plug-in harness. A trial run at about 2600 rpm for about 50 minutes was good. I went fishing and ran the boat for at least another 50 hours. Then the same thing again. One day I heard a slight rev in the engine a couple times. Then it revved hard and kept running. About 10 minutes later, it revved hard and quit. I turned the key switch and got no sound such as key switch buzzing or starter solenoid clicking. After about 10 minutes, I turned the key switch, got a buzzing sound, and started the engine. I idled back to the harbor miles away. On the way back, the engine revved and quit 3 more times. Each time though with no 10 minutes waiting period, I turned the key switch, got a buzzing sound, and started the engine.

Any ideas on the problem(s) would be greatly appreciated. Thank you.

Topic

[Rob Schepis]

The buzzer is powered by the power that is fed through the harness to the instruments via that engine mounted circuit breaker that Tony referenced. Whether or not the buzzer sounds is controlled by the PCB at the helm instrumentation.

Can you elaborate more on your comments about the engine “revving hard” ?
What type of controls do you have ?

[Joe Faith]

Mr. Athens,

Thank you very much for your help. I live in Alaska where it has been cold lately (5 below zero this morning). When it warms up more, I’ll go out on my boat and look for loose wires or anything else that doesn’t look right.

Also, last summer, the engine always started when I turned the key and heard the buzzing sound. It never started when I turned the key and did not hear the buzzing sound. What controls the buzzing sound?

Thank you for your time and consideration.

Joe Faith

[Tony Athens]

100% this is an electrical issue………………Look the the picture.. Seen on these these on your engine?? 99% this is the issue–Loose wires or ??

[Author]

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