Red Hot Ground Jumper

[perkdp]

on a 2009, 25 hp, 2 stroke.... was wiring lights to the boat (aluminum). touched only one light wire to the hot battery post... the ground jumper on the motor, behind the transom sparked and got red hot. apparently the light was wired in such a way it caused a dead short back through the motor's ground wire somehow. question is, could it have damaged any electrical on the motor ?

 

[99yam40]

Re: Red Hot Ground Jumper

It is a good idea to fuse everything coming off the battery except the main cables. That way you just blow a fuse instead of melting wire and causing other problems when you short things. Sound like you shortrd a hot wire to the boat and it tried to get back to the battery negative on the motor block, taking the path through the bonding jumpers as it does not flow well through the rubber motor mounts and plastic bushings

 

[perkdp]

Re: Red Hot Ground Jumper

that's what i figure happened. how likely is it that it fried some electronics in the motor ?

 

[AGENT 37]

Re: Red Hot Ground Jumper

Hooking up battery cables backwards will also do this.

 

[99yam40]

Re: Red Hot Ground Jumper

that's what i figure happened. how likely is it that it fried some electronics in the motor ?

Not absolutely positive, but I do not think it would if that is all that happened

 

[perkdp]

Re: Red Hot Ground Jumper

update: when running two 55 watt halogen lights, 15ft of 14guage wire, lights grounded to alluminum boat, motor has positve & negative on battery.......

if the hot wire only to the lights is connected, the ground strap on the outboard starts to heat up. (apparently using the motor's ground back to the battery)

if the hot wire and ground wire to the lights are connected, the ground strap on the outboard is not affected.

 

[99yam40]

Re: Red Hot Ground Jumper

That is good you got is taken care of.
Yes ,it is never a good idea to use the boat hull as a ground path, especially if you do not run a ground wire from battery to the hull.
Even if you do ground the hull the chance of setting up some electrolysis that will eat the aluminum hull is good

 

[perkdp]

Re: Red Hot Ground Jumper

Wow, I forgot about this thread... I don't like when I find an open ended thread on this forum so I'll update it.
I appologize for the delay.
Confirmed by Yamaha mechanic... without a ground wire to the battery for the lights, the circuit tried to complete using the motor's wiring and the boat. This is a common problem especially with Yamaha.
Always use positve and negative wires for add-ons .