Little Red Button on Cummins 6BT-5.9M

[nveater]

So disclaimer- I am a former sail boater whose largest engine was a Yanmar 3gm30f- now I have this "monster" (to me) Cummins diesel. I was getting acquainted with my new friend, I noticed this red button on the aft port side of the engine with the #10 on the top. Can anyone tell me what this is ?

Thanks

 

[LarryM]

It is the 10A circuit breaker which supplies power from the positive side of the battery/solenoid connections on the engine to the ignition switch via the wiring harness and instrument panel. Should be a Red wire.

 

[DWJensen]

So disclaimer- I am a former sail boater whose largest engine was a Yanmar 3gm30f- now I have this "monster" (to me) Cummins diesel. I was getting acquainted with my new friend, I noticed this red button on the aft port side of the engine with the #10 on the top. Can anyone tell me what this is ?

Thanks

Perfect timing and great question. Recently closed on our trawler (having come over to the dark side from an IP with a 4JHE) and I noticed that our 6BTA5.9 Cummins has the same red button. Seller didn't know when asked and I haven't yet read through the entire engine manual, so I'm looking forward to seeing some replies....

 

[RT Firefly]

Greetings,
Red Buttons....

 

[High Wire]

Don’t ever push the red button!

 

[firehoser75]

NVeater and Daz,
Welcome to owning a Cummins 6BTA. They are great engines (with a couple of weaknesses) and will give many thousand of hours of service if well maintained.
Do yourself a big favour and go to sbmar.com (Seaboard Marine's website) owned by Tony Athens, a marine diesel guru, especially all things Cummins.
Yes, it is a commercial site where he sells products and services, but he gives freely of his vast knowledge accumulated over 30 plus years of experience, both with answers to questions on his forums, but with tons of articles under "Tony's Tips".

Your photos show an engine that "looks" like it has been looked after.

Potential issues to consider addressing on this engine include:

1) Idle pulley bolt replacement.

2) Replacing the Sherwood raw water pump with a much better (but same or cheaper priced) pump from Seaboard.
3) Replacing the Walker Airsep with a better CCV system, especially if your turbo shows signs of oily buildup.
4) Installing a freshwater flush system. See articles about "Marine Age".

5) If still using the stock Cummins (white double jacketed exhaust), changing that out to a custom exhaust (see the article on sentoa.org under tips "Cummins wet exhaust issues on early NT37 by Kelly Britz). This one is very important.

6) Regularly service your Aftercooler(s). Every 3 years or so, unless freshwater flushing then maybe every 4-5 years.
You have received a good answer for the "red button".
Enjoy your great engine.

 

[DWJensen]

It is the 10A circuit breaker which supplies power from the positive side of the battery/solenoid connections on the engine to the ignition switch via the wiring harness and instrument panel. Should be a Red wire.

Thanks Larry - Apparently we were posting at the same time and I didn't see your response until just now, thanks for the info.

OK, so it's a breaker, but what is its purpose - Will pressing it just kill power to the instrument panel(s), or does it act as a cut off like turning off the key?

 

[DWJensen]

NVeater and Daz,
Welcome to owning a Cummins 6BTA. They are great engines (with a couple of weaknesses) and will give many thousand of hours of service if well maintained.
Do yourself a big favour and go to sbmar.com (Seaboard Marine's website) owned by Tony Athens, a marine diesel guru, especially all things Cummins.
Yes, it is a commercial site where he sells products and services, but he gives freely of his vast knowledge accumulated over 30 plus years of experience, both with answers to questions on his forums, but with tons of articles under "Tony's Tips".

Your photos show an engine that "looks" like it has been looked after.

Potential issues to consider addressing on this engine include:

1) Idle pulley bolt replacement.

2) Replacing the Sherwood raw water pump with a much better (but same or cheaper priced) pump from Seaboard.
3) Replacing the Walker Airsep with a better CCV system, especially if your turbo shows signs of oily buildup.
4) Installing a freshwater flush system. See articles about "Marine Age".

5) If still using the stock Cummins (white double jacketed exhaust), changing that out to a custom exhaust (see the article on sentoa.org under tips "Cummins wet exhaust issues on early NT37 by Kelly Britz). This one is very important.

6) Regularly service your Aftercooler(s). Every 3 years or so, unless freshwater flushing then maybe every 4-5 years.
You have received a good answer for the "red button".
Enjoy your great engine.

Thanks Tom, looking forward to many years with this one. Mine's a 2019 factory long block with the new pulley system and she has a new (2020) custom exhaust. Not sure on the raw water pump, that's another "to look into" item for my list. The aftercooler was done in 2019/20 when the new long block was installed.

Thanks for the comments and input, such a great resource.

 

[C lectric]

Thanks Larry - Apparently we were posting at the same time and I didn't see your response until just now, thanks for the info.

OK, so it's a breaker, but what is its purpose - Will pressing it just kill power to the instrument panel(s), or does it act as a cut off like turning off the key?

A circuit breaker is intended to protect the wiring from to much current, either from an overload or from an outright short circuit. Unless one of these occurs it will remain closed for operation.

THose C.B. are a push button to RESET only. They do not operate as switches.

Look up on Seaboard's site the wiring for these engines and you will see it is powered from a connection to the starter motor solenoid which is a heavy cable intended to start the engine. Were it not for the C.B. there would be a heck of a serious problem if a short circuit developed in the wiring after the C.B., thus the C.B.

 

[LarryM]

Thanks Larry - Apparently we were posting at the same time and I didn't see your response until just now, thanks for the info.

OK, so it's a breaker, but what is its purpose - Will pressing it just kill power to the instrument panel(s), or does it act as a cut off like turning off the key?

Pressing it does nothing unless it has opened for some reason. Then, it will reset the breaker. When it opens, it will be slightly extended maybe 1/4" or a bit more.

It does not work like a switch to control the circuit. It's just a circuit breaker.

It protects the always hot B+ circuit in the engine harness. It only opens in the event of a short, or too much current being drawn from the instrument panel/helm connections to the circuit.

 

[nveater]

Thanks for the responses. I actually attached a solenoid for the starter on my Yanmar 3GM30f because of starter issues. I have "joined" Seaboard's forum and ordered suplies from them. I appreciate the tip for the engine- I know the PO did the idler bolt. I shall not push the red button

 

[Steve DAntonio]

Most modern diesel engines have a circuit breaker like this, or a fuse, it supplies power to the entire instrument panel. If it trips, you lose all power to the panel, including key switch, and the engine will not start. You should know where yours is located, again some are buttons like this (if it's not tripped pushing it will do nothing) or a fuse, or fuses (recent Deere and CAT I inspected each had three fuses).

 

[AlaskaProf]

Don’t ever push the red button!

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