Blown fuse or worse?
 

OK here is what happened, I was catching up on some needed boat maint. I had taken my battery out to re-charge it. After re-charging I went to put it back in and (yes, I feel stupid) I hooked the cables up wrong (red to neg , and grnd to pos). I knew this immeditately because it sparked. After hooking the battery back up correctly, I had no power at all to anything. I checked the 90 amp fuse at the starter with a volt meter and I have power going thru it. The 50 amp fuse near the ECM was tripped and I could not push it back in to reset it. I also had no power running thru it. I ordered a 90 amp and 50 amp fuse. I believe I have only tripped the 50 amp fuse. Could I have also damaged the voltage regulator in the Alternator and if so can I also just check this with the volt meter? Anyone have any input on anything else I may have messed up. The boat has a 7.4l MPI . thanx.

Dont lose any sleep over it. Connect the battery properly and with the battery connected press the reset. If current is not getting past the button then install a new breaker. Everything should be fine.

The alternator on that motor does not begin charging until you exceed 1500 rpm once. You should see over 13.5 volts running.

Andy Thanx, I did that but still nothing, It was stuck in the open ( I believe blown position), It will not reset.I have the new breaker on order. I figured I blew it and it protected the rest of the system. I just dont want to re-installl a new one and have it blow for failing to check something else. thanx again.

on those breakers you sometimes really have to push hard to reset it, almost to the point of hurting your finger, it will probley reset just push hard,

OK thanx, I will try that.

I did the same thing, same motor if that makes any difference. A couple of fuses and I was good to go. I may have gotten lucky. The only one I had to hunt down was an inline fuse for my amp. Until I found the inline fuse blown, I felt lucky I had only (thought I had) blown up the stereo and or amp.

Hey Rough water, I tried that, even with some vise grips and it would not reset, do I need to have the battery connected to do it?

Sea ray Jim, what fuses were blown on yours? I think my 50 amp reset fuse near the ECM is blown for sure. Pretty sure the 90 amp near the starter is good ( I ordered both in case ).

NO IF IT WOULDNT RESET WITH THE VISE GRIPS THEN YA IT TOAST, BUT YOU SAID YOU ORDERED ONE, SO NO SWEAT RIGHT? YOU COULD USE A JUMPER WIRE AND GO AROUND IT FOR NOW WITH A EXTERNAL FUSE JUST SO YOU CAN CK EVERYTHING ELSE AND SEE WHAT ELSE YOU MAY NEED IF ANYTHING, CHANCES ARE THE BREAKER TOOK THE BULLET FOR EVERYTHING ELSE, THATS WHAT THEY ARE THERE FOR, :cool:

I have a stupid question. Why would a breaker or fuse trip/blow on reversed polarity? Typical breakers/fuses trip from excessive amperage load.

Is it this: Positive side of battery is now grounded to engine block. Battery circuit is then completed through negative side of the battery which is hooked to the boat electronics. Therefore, in order for current to flow to the engine block out the positive side of the battery, the negative side has to flow an equal amount of current. Cool. So effectively you flowed 50amps of current through any device that had a path to ground (ie the switch was on). Guess that is why Sea Ray Jim's amp fuse blew... switch must have been on or a different path to ground through the amp.

Now that I think I answered my own question, I'd look around the boat for anything that may have been switched on at the time, and check it out. Bilge pump comes to mind first.

Good luck and thanks for clearing that up. ;)

BT :cool:

THATS A INTERESTING POINT, THE FACT IS THAT THE BREAKER IS MEANT TO POP AT 50 AMPS OR WHATEVER VALUE WE ARE DEALING WITH, AND THE AMPS PROBLEY SPIKED WELL ABOVE THE 50 MARK THUS TRASHING OUT THE BREAKER, WEATHER IT HOOKED UP CORRECTLY OR NOT THE BREAKER DOESNT CARE, YOU COULD TAKE A 10 AMP BREAKER AND HOOK UP LIGHTS ONE BY ONE TILL THE BREAKER BLOWS AND IT CAN BE RESET BECAUSE YOU HAVE EXCEEDED THE PREDETERMINED VALUE BUT NOT BY MUCH, THEN TAKE THE SAME BREAKER AND HOOK IT UP DIRECT SHORT ON THE BATT POS TO NEG AND OF COURSE IT WILL POP BUT! IT WILL NOW BE JUNK AND WILL NOT BE ABLE TO BE RESET BECAUSE THE AMPERAGE THAT HAS SPIKED THROUGH IT SO HIGH FOR A MOMENT THAT IS HAS MELTED OR WELDED BASICLY WASTED THE RESETABLE COMPONET IN SIDE, I DONT KNOW, AFTER YOU HAVE BEEN IN THE REPAIR FEILD FOR A WHILE YOU GET TO A POINT WHEN YOU DONT CARE HOW IT WORKS, JUST SO LONG AS IT DOES, YOU THINK IM BURNED OUT?