Trouble replacing ground lead wire

[PhuOnGsta]

Hi, im new to this so excuse me if I seemed a little
confused.

so the issue I got after a day on the water i started getting This white powdery corrosion of some sort around my lower motor. Also under the entire boat (aluminium boat) i didn’t know what it was so wasn’t too concerned but taking it out following week it happened again even more white milky powdery looking thing all over. Now I’m worried, I’ve hit it with WD40 and seems to have kinda loosened it up little in heavy parts. I then noticed a wire had been snapped and by looks of it in 2 places. (Running a Yamaha 100hp 2003 4 stroke) for the life of me I don’t know how to get in to the lower case to change the ground lead wire.

I’ve looked it up online and see that it’s a double wire that goes to the grease nipple and the other end runs into the lower unit but I don’t know how to get to the bolt inside the housing where the water or speedometer hose I think goes.

Can someone help please be so much appreciated

[boscoe99]

Remove the lower unit. Look up within the upper casing.

[PhuOnGsta]

Hi Boscoe99 and thank you for the prompt response.

so as per the diagram the bolt actually points upwards? If so that would be much easier... I was going to drop the lower unit this morning and have a look but worried bolt would be horizontal so didn’t want to waste time..

thank you so much Boscoe99 you saved me a trip to the service centre and money in pocket.

I’ll do this next Sunday and let you know how I go... thank you again life saver.

[PhuOnGsta]

Hi biscoe, I just replaced the ground wire and out it all back together and connected the battery. The wire started burning. The wire that runs down all the plastic burner off it. What could be the problem? I undid all nuts bolts and replaced as they came off, also greased them after. I’m stumped. is there a way or are the not meant to touch anything?

[Bluefish]

If you’re smoking those wire’s, you have a bad ground from the battery to the engine, also check that the wire isn’t corroded going into the connecter.
You’re grounding through the lower unit to the water

[PhuOnGsta]

.Hi bluefish, so what would you suggest I do? Disconnect all my batteries and check the grounding? Is it possible my isolator switch is faulty?

I hadn’t touched anything to do with the battery connections besides replacing battery. But that is straight forward terminals off and on.

also is it safe to leave that ground lead wire on without the protective plastic which burnt off the wires whilst I find the faulty ground?

initially this morning before I undid everything I took off this side cover, and as I was undoing the bolt, my ratchet touched the ground wire which was already snapped and it smoked up. The actual wire smoked