Another boat fire.......

[TnRiver46]

I’ve had 3 fires in my boat now, luckily all the size of a bic lighter flame. Last night it was in the parking lot thank goodness and it was this wire which I’m guessing is a ground. Everything seems to function normally still even though the wire burned in half..........

 

[Way2slow]

That's the ground strap that grounds the motor mount to the main engine.  The only thing that could have caused that was the T&T motor or wiring going.  The first thing I would do is take a volt meter and see if I read voltage from the end in the picture to the negative post on the battery.  If there is voltage, that means there is still a short on that motor mount.   A fairly large positive wire had to have shorted to the mount to cause that, one that could handle more current than that ground strap.  When a short happens, the smaller current source is the one that smokes, so the what ever shorted had to have been a bigger/better conductor than that ground strap.  The T&T motor has fairly large wires going to it so I would make sure none have worn and shorted where they go through the hole in the mount.

I would the cause because next time, you could be on the water and it get inside the motor cover, bad things could happen then.

[TnRiver46]

8 minutes ago, Way2slow said:

That's the ground strap that grounds the motor mount to the main engine.  The only thing that could have caused that was the T&T motor or wiring going.  The first thing I would do is take a volt meter and see if I read voltage from the end in the picture to the negative post on the battery.  If there is voltage, that means there is still a short on that motor mount.   A fairly large positive wire had to have shorted to the mount to cause that, one that could handle more current than that ground strap.  When a short happens, the smaller current source is the one that smokes, so the what ever shorted had to have been a bigger/better conductor than that ground strap.  The T&T motor has fairly large wires going to it so I would make sure none have worn and shorted where they go through the hole in the mount.

I would the cause because next time, you could be on the water and it get inside the motor cover, bad things could happen then.

Thanks again, I've been having intermittent t and t issues and I think there's a thick wire going into the cowl that looks rough. 

[Way2slow]

Forgot to mention, you need to replace that ground strap.  Without it, the T&T motor is having to depend on metal to metal contact in the pivot or something else for a negative source.  Meaning, if there is no metal to metal contact, the T&T is not going to run or run much slower if there is much resistance at that contact point.

 

Also, normally the wires that are large enough to carry that much current are red, but that may not always be the case, but I would be checking all the larger red wires first.

[TnRiver46]

I took the plastic off the middle section and here’s what I see. Where does the broken/burned wire connect to? I don’t see anywhere to replace it 

[Way2slow]

Look on your mounting brackets that bolt the motor to the boat, maybe right on the very bottom.  The T&T is mounted inside the motor mounts so it has to bolt to them somewhere.  You should be able to find the other eyelet with maybe a little of the ground strap sticking out. (or the T&T housing)

After seeing your picture, there won't be any voltage on that piece. I thought from the first pic that was mounted to the motor mount, but that's the other end that ties it to the midsection and the midsection is bolted directly to the block, which probably also has a ground strap but may just depend on the physical connection since it has several very large studs mounting it.

If the short still exist, the motor mount will be showing a voltage between it and the battery negative, (make sure you get on bare metal, the paint don't conduct) or the midsection/block, or between the motor mount and the bolt holding the burnt wire.  There should be absolutely no (zero) voltage showing on the voltmeter when you check it.  If the positive source burnt itself clear, it will come back, and this time, if it can get a good enough ground through the pivot, it's going to smoke the wires in the motor and possibly cause a fire inside it.  That could ruin your day.

 

One other thing, if it has enough resistance to keep from setting itself on fire, it will most likely drain you battery.  So if you wind up with a dead battery, you will know what caused it.  So, basically, I would disconnect my cranking battery until I found the source of the short.

[Way2slow]

Looking at your bottom picture, I see something that doesn't look right to me.  That U shaped bracket at the front of the bracket that wire is bolted to, going around the swivel shaft, I see daylight between the shaft and that bracket.  I would think there is supposed to be a bushing there.  You can go online and look at a parts diagram of your motor and see, but my basic knowledge of how things work says it looks like there is something missing there.  That may just be a support bracket for that lower mount, but from the picture it doesn't look right with the end of that shaft sticking down unsupported.