tripped main circuit breaker????

have considered changing the name of this boat from Barefoot Nautique to PADDLE NAUTIQUE!! found the problem....an alternator wire was resting on the manifold and had burned the cover from the wire. it was shorting out on the engine block. fixed the wire and re-routed everything. ran the boat this morning with Tarheel and for the first time, we didn't need a paddle to get back to the dock! carb has just been rebuilt and is not dialed in yet (i am no mechanic or carb genius), so i will need to get someone that knows what they are doing to dial it in. it is running a little rich, blackening up the back of the boat just a little bit. not much, but enough to annoy me and make cleaning it up a pain in the butt. boat is running about 140 degrees according to the gauge, this seems a little cool, what do others think???? maybe a thermostat change is in order?? it will run about 135 range some, then up to 140 at others, and when idleing, it will run about 145. i am thinking that is too cool for this 454 PCM. thanks for everyones help on this board and thanks to Tarheel for being my primary "paddle pilot" on the last day if left us stranded on the lake!       

Im happy to see Jim in Houston with ohms law behind him!! I can say this, its not an accessory thats the problem because those are fused individually at the dash. The main breaker is usually pretty hefty and is designed to protect the big (If you call #10 wire big) feed wire up to the fuse panel in case it shorts out, and in case the alternator shorts out. Corroded connections might cause them to heat up, but will actually draw less current as the voltage drop increases. people get this confused from house current which is A.C. and can cause current to rise with a lower voltage. These items are loads known as inductive loads(motors, welders, refrigerators etc.).
Check the main wire leaving the breaker for cuts. If OK, then turn all accessories on and see if breaker trips. If it doesnt, the breaker is probably good.

It could even be a weak breaker. If it was I would run the boat and see if the breaker trips again. Pay attention to what you are running when it trips. I know of nothing except corrorded and shorted wiring that pulls enough current to trip the beaker (except a faulty electrical device).

Bilge pumps are not wired through the breaker are they? What about exhaust fans? If those items are wired through the breaker a shorted motor in one of those items could trip it. (But they may not be wired through the breaker.)

If it trips and you have a carburator try disconnecting the choke (the hot wire not the wire that is "grounded" to the chock itself.)

Except for terminals or wires shorted together or a failed device (fan, pump, electric choke, horn, lights, etc) there is not anything else that can cause it to trip - unless like I said, it has gotten weak with age.

Are you running any kind of monster amp?

My advice: Go run the boat and see if the breaker continues to trip. If it does pay attention to any devices that may have been operating.

UPDATE......now i have discovered that i don't think my boat has a "circuit breaker" like the COMMANDER engines do... does anyone know for sure if a 454 PCM will have one?? i am not near the boat at this time, but will be later tonight. i guess i will be having fun with a test light later today. !!

pc

Boy, that's a bad day nautiquefanatic. If your boat had only died in front of your cousins place and his '84 was running; maybe he could have helped you. I bet I've been towed as much as anybody here. Sorry I wasn't able to help you, but maybe next time. Your boats need to run so I can rely on you to tow me home. That's a bad boat and can't wait to ride in it.

Check the main engine to boat wiring harness connector for corrossion. Corrossion on an electrical connection causes high resistance which in turn increases the amperage required to maintain voltage across the connection. Often there is enough resistance across a bad connection to exceed the capacity of the circuit breaker. Clean up all connections and apply a dielectric grease upon reassembly.