Battery Connections rusted to Slave solenoid and to ground

[Newbie1zzz]

Replaced new Battery terminals, Because boat was not starting, Now in following the battery terminals there are bad connections to the( starter solenoid) think I am wrong about this... Both positive and groud wires are rusted broken, Is there anything I have to be careful of when attempting to replace these wires? I want to totally disconnected the Battery to do this. seems to be the problem to me, not getting enough juice. . Help please..
Did a little more looking and it may be the wiring to the starter, Wish I had a photo of all it looks like with the parts listed on it. This a 4 Cylinder Mercruiser inboard motor that was not well kept. Thank You for your help.

 

[glenn property of pam]

Re: Battery Connections rusted to Slave solenoid and to ground

model and year of the motor would help. If you know where everything goes then disconnect the battery and replace or repair one wire at a time and use quality parts like plated rings with heat shrink. If the large cables have bad ends then they were most proberly automotive cables and should be replaced (at the very least crimp quality ends on them as the auto stuff will rust and break). If you are unsure how a wire is connected then do not guess as thats a expensive game to play just take a picture of the area and the wires then list where each comes from (large cables) or color of the wire on the smaller wires