02 mercury 50 generic wiring problem

ok got me a little tracker pro team 165 with a 2002 mercury-tracker 50 and last summer it had a major wiring meltdown around the voltage regulator, talked to local boat mechanic he said
400 to fix included new regulator and all the burnt wires redone. did all that and shes runnin good again and charging right etc. BUT after he pointed out the fact that since i had my deep cycle
hooked to the engine and trolling motor and everything else thats probably what caused it to blow because i was pulling way to many amps off the battery for the little 50
to put back in and it just tried and finally blew. so now i got 2 batterys a regular 12 volt for the engine and all my guages, radio, etc, and the 12v deep cycle is ONLY hooked to
my trolling motor and it has enuff power to pull my little tracker all around all day its an aluminum boat and the biggest baddest deep cycle autozone had and its a 45 lb
foot op but i dont troll all day anyway i usually run out my spots and maybe troll 2 hrs max all day so that batt still got tons power left. so just charge it at home with a plug
in charger and let the 50 charge the other isolated batt. ok sounds all good so far right? well after charging the regular batt, SOMETHING is drawing power off it with the key
OFF. so now im really confused because nothing should be drawing off that with the key off what my worry is that somewhere theres a short or something and the mechanic said
if there is ghost short that could cause another meltdown which im DESPERATE to not have happen again. so thats where im at and im needing advice, so if
anyone has any ideas on how i can figure out whats drawing power or what i should do please advise

kimcrwbr1 said:

There could be a internal short in the loop somewhere and definately you should track it down. Do you have a disconnect at the batteries? What I do is confirm the ground wire to the helm is isolated and not shorting to anything. Disconnect the battery and then pull all the fuses and then start isolating individual wires end to end and check each wire in the loop. It can be real time consuming but you will know every wire in the boat is good when your done. If you have a long wire you can use just jump it to the wire your testing at one end and use you vom on the other end and test for a short on all other wires. I just use the ground so I dont get confused and have to start again. If you do find two wires shorted together that should not be it may be easier to just pull two new wires and terminate the bad ones. That is why you fuse everything coming off the battery and then again fuse all other appliances at the helm.

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thanks for your help, ill look tomorrow and say for sure whats coming off the starting battery but i THINK its the one big hot and one big neg going to the motor and then like one or 2 smaller hots, colds, going to dash, or ash you say helm, like proper boat talk lol very cool, and yeah theres a fuse block up there under the trottle controls and the boat was cared for and hasnt seen much weather but maybe a tad. theres a tad of corrosion very minimal though. i didnt think to pull fuses and stuff im just not super great with wiring i can manage basic stuff though. heres another thing i thought of, just make a couple clamps back there and ONLY have the big engine wires hooked up while the engines running so basically that way bypass any short and the boat will run and batt be charging etc but just no gauges but really dont need them to run out. then when i get to my spot i hook up the clamps and its a small drain so if im playing the stereo whatever it aint pullin much and it plays with key off can flip it on check gas if need whatever, then unhook dash when ready to run again, it seems in theory it would work but heres a nagging question, how does the starter know when to turn if the dash IS hooked up lol, cus i dont see any little wire going to the engine so even when u do turn the key how does it tell the starter to turn if theres no wire going back there, am i missing something or what

Some times you can luck up and see a tiny arc when you disconnect or connect wires to the positive post on the battery...you can do a touchy toughy with the wires and see it...
do you have a multi meter and know how to use it?
i run with nothing connected to the starting battery but the motor wiring and the bilge pump....this will include your dash of course...nothing will be added to the dash wiring such as radio etc...so if i was you i would move the radio and anything else to the trolling motor battery...you dont want any draw on your ignition battery with the switch off..in addition to running the battery down you are exposed to shorts etc that can damage or destroy the regulator or power pack with all that other crap on the ignition battery...
in answer to how the starter circuit works....first lets look at the key switch...when the key is turned off the switch feeds a ground to your power pack to kill the motor...when you turn the switch on the circuit to the power pack floats..no voltage and no ground...you do have voltage to your dash...then when you turn it to start a voltage feeds through the neutral switch and then the ignition switch to pick your solenoid and away you go.. you dont have a single wire going to the motor...its all in the harness going to the big plug..
with a multimeter you should read infinity to ground on every wire coming off your battery with the switch off...if not you are going to pull some current...