Cummins Marine Diesel Repower Specialists › Forums › Cummins Marine Engines › 6cta not starting & wire burning
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December 26, 2021 at 7:52 pm #124407
NetoParticipanti am having issues with one of my 6cta engines, when i try to start the engine sometimes it doesnt start and the positive wire in the bendix gets really bot that it starts to burn through the insulation… It feels like there is a big short somewhere… What could be causing this? maybe a bad bendix or starter? i did change the magnetic switch but that didnt do anything…
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December 30, 2021 at 7:44 am #124543
Your problem has nothing to do with the number of banks. There have been countless arrangements of battery banks for boats, all have their pros & cons. Two banks where one bank starts the engines and the other handles the house loads and where there are provisions for combining both banks and isolating a bad bank for emergencies is the best compromise for most installs IMO. Leave that alone and remove your starter & get it tested.
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December 30, 2021 at 6:30 am #124540
NetoParticipantWhat is the best practice for the starting batteries
Is it better to have one bank with 3 batteries to start engines and generator? Or should I separate these and have independent banks? Right now i have two banks but I will rewire if necessary after inspecting and cleaning all the connections. I believe my battery charger has the capability of charging 3 separate banks.
December 30, 2021 at 5:55 am #124539Thanks for the correction, my reply was poorly thought out.
December 29, 2021 at 7:42 am #124510
Gene FullerParticipantVessel Name: Yorkshire Rose
Engines: QSB5.9 380
Location: Punta Gorda, Florida
Country: USA
Sorry, that is completely backward. A bad connection increases the ohms, which *decreases* the current in the wire.
There will be more heating at the bad connection, but less heating in the remainder of the wire.
Gene
December 29, 2021 at 7:11 am #124504Could be starter or bad connection at the starter.
Bad connections cause heat from high amps. (Ohms Law)
high amps will always be high amps in the entire wire, not just the end. (from the poor connection to the source of power)
December 29, 2021 at 5:08 am #124492
NetoParticipantThanks for the replies folks! My guess was that the bendix got stuck and pulled enough current to burn some wires.. Someone in the marina told me to remove the bendix and grease it, I did that and seems to be working now. I do have to bypass the big red wire and the battery disconnect switch with a straight wire from the batteries to start this engine, seems that a wire got burned in the connection box or some bad connections… I will take out everything, clean it and re-install new cables if necessary..
December 28, 2021 at 12:13 pm #124469
Clark LeighsParticipantEDIT:
I see you said it is the big red wire that gets hot and is cooking the insulation. Missed that.
Yes, it could be a problem in the starter motor.
I will still question where wire #3 goes. Although I doubt it the short could be down that wire also IF the two wires, #1 & #3 are indeed attached to the same stud on the starter motor.
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December 28, 2021 at 11:04 am #124463
Clark LeighsParticipantI see several wires. Which one is getting hot?
#1 THe big red one. That should be the positive from the batteries.
#2 The smaller white one that runs from a bolted connection on the actual motor end to a bolted connection at the solenoid base.
#3 I also see another white wire in the background which LOOKS like it goes to the same terminal that the big red wire attaches to. But does it?
Which wire specifically is getting hot?
Can you take a copy of the photo and repost it after indicating, pen, which wire is affected.
From here it sort of looks like the wire in #2 but can’t see well enough.
Also take a photo of the solenoid end. I think I recognize that starter as quite similar to mine. They usually have a dedicated ground terminal which is meant to be the ground back to the batteries or at least to a serious ground on the engine block, [Not as good}
December 28, 2021 at 10:15 am #124456
Gene FullerParticipantVessel Name: Yorkshire Rose
Engines: QSB5.9 380
Location: Punta Gorda, Florida
Country: USA
Bad connections and terminals could cause a lot of heat right at the connection, but they will cause less current to flow in the “entire wire”. If the entire wire is getting hot then there is too much current. Most likely a problem in the starter.
Gene
December 28, 2021 at 12:17 am #124447
NetoParticipantthe entire cable gets hot (red on picture) and starts smoking. Both engines and generator batteries are in parallel on this boat… Something is causing a short sometimes before engine starts, once engine starts then everything works well.
December 27, 2021 at 6:22 pm #124444
Clark LeighsParticipantWhere specifically is the wire getting hot? Are you referring to the wire that attaches to the heavy studs on the starter mounted solenoid?
If so where exactly is the wire getting hot? At the crimped on terminal where the terminal is attached to the wire.?
If this is the case then most likely the crimped on terminal is not crimped properly. It could also be that the nut holding that terminal is not tight enough causing a poor connection.
Check it out. Don’t just look at it. Disassemble the nut and terminal and clean all of it. Disable the battery end or you will have a light show that won’t be amusing. A tiny wire brush can do a good job. Clean the terminal. Then put some anti corrosion or dielectric paste on lightly, don’t need gobs, and tighten it up.
One other thing I would do is recrimp the terminal. You may have to borrow someone with one to do that. Ask around the marina. It that terminal still gets hot then you simply may have to replace it.
I am making some assumptions here about the where the hot wire is. You description is not really clear. Can you post a photo or two , good clear ones, that show what you are referring to.
As for the Cole Hersey push button, NO. All that P.B. does is activate the magnetic switch you replaced. It has nothing to do with carrying the very heavy current the actual starter motor itself needs to work.
December 27, 2021 at 1:27 am #124409
NetoParticipantthe wire that gets really hot is the big one from the battery to engine. Once engine starts everything seems to be in workinf order, could it be the cole hersey push button getting stuck?
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