My issue is the following, boat runs great all day, once it is "hot" the 50 amp breaker will pop. After resetting it, boat runs but starts having an issue with what I believe is the timing, starts backfiring through carb.  Running HEI ignition, Indmar 454. Bad breaker? or something else. Someone suggested that it could be an alternator problem or battery issue. Any thoughts?

You have a short somewhere. Nothing in a jet boat should draw 50 amps...

If there was a short, wouldn't it do it when motor is hot or cold? Seems to only do it after its been running for awhile.


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Do you have individual fuses for things? Or just everything on a single 50 amp? Surprised you don't have a burned wire. 50 amps will toast smaller gauge wires.   

No burnt wires, everything works until the breaker trips. Then once I reset it I start having the backfire in carb. I know, sounds crazy.

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Sounds like something in the ignition circuit. Does it pop the breaker as your running? How long after cooling down will it run correctly again. The hotter wires get the harder it is for current to flow so see if any wires are hot, loose or faulty connections. Maybe also have the battery load tested.


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Happens only after the boat has been running for awhile, ran from Thompson bay to steam boat on havasu and breaker popped well at full throttle, lost all power..  Have to wait for breaker to cool down (aprox 5 min) before it can be reset. I can honestly tell you, that the batteries are fine. Why, you might ask, well that's what I do for a living. I am a battery distributor.   

Your alternator my be over charging the system and blowing the breaker. To much charge will screw with the coil and timing will sound off.


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 That might explain why it only pops after running for awhile. Causing the breaker to get to hot....

I vote wire connection is getting hot. Just a guess though. Make sure you post up what it turns out to be. Got me curious.


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Thinking faulty ground.


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Does that systems have an on sensor in it ? If so I've seen those things pop those fuses

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No o2 sensor. I'm guessing alternator. I'll have an answer tomorrow hopefully.

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Stupid question but what size wire do you have between your ignition and your starter?  Had a hot rod that had the same problem couldnt figure it out.  Some old drunk at a show said change the ignition wire to a #10 at least.  Thought he was full of shit.  Thought it couldn't hurt though.  I'll be damned if it didn't fix the problem!   Dont know why......

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Any idea what alternator you have? Are you running a voltmeter or an ammeter?

Here is a little test to try and narrow it down. Run a 10 gauge wire from the post on the alternator to the positive side of the battery and run it again.

If it wired in the conventional sense, the power from the alternator goes to an orange wire, all the way to the dash and back. these wires would traditionally go "through' an ammeter and they would typically have a 35 am alternator.

On most boats, they use an internally regulated alternator, the exciter wire is the voltage typically to the dash ign. wire. This tells the alternator the condition of the charge. If the alternator is seeing too low of voltage from the exciter wire, the alternator will full field and definitely cause the breaker to trip. It may not do it when the boat is "cold" because the battery has not yet reached full charge.

I am grasping at straws here, but this experiment wont hurt anything and is totally reversible.

GT

Any idea what alternator you have? Are you running a voltmeter or an ammeter?

Here is a little test to try and narrow it down. Run a 10 gauge wire from the post on the alternator to the positive side of the battery and run it again.

If it wired in the conventional sense, the power from the alternator goes to an orange wire, all the way to the dash and back. these wires would traditionally go "through' an ammeter and they would typically have a 35 am alternator.

On most boats, they use an internally regulated alternator, the exciter wire is the voltage typically to the dash ign. wire. This tells the alternator the condition of the charge. If the alternator is seeing too low of voltage from the exciter wire, the alternator will full field and definitely cause the breaker to trip. It may not do it when the boat is "cold" because the battery has not yet reached full charge.

I am grasping at straws here, but this experiment wont hurt anything and is totally reversible.

GT

Voltmeter, Leece Neville alternator

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