Engine Circuit Breaker

[cannonman]

My 2005 Mercruiser 5.0 died this weekend because the 50 amp engine circuit breaker tripped. I could reset it after a few minutes and the boat would run fine for several miles then stop again when the breaker tripped. This was repeated several times before getting back to our dock.
I can't find any reason for this breaker to trip. Do they get weaken and go bad?

 

[Don S]

Re: Engine Circuit Breaker

What's the serial number of your engine?

You don't have any accessories coming off the engine harness except for the instruments and ignition switch do you?

 

[cannonman]

Re: Engine Circuit Breaker

Don, I thought I had something at home with the serial # on it, but I don't.(The boat is at the lake, 100 miles away).

I did some checking last night on the circuit breaker that I removed and brought home. The only way to get continuity through the terminals is to manually hold the red button in. This seems backwards to me. Shouldn't it be normally closed until it pops open when a problem is detected.
I'm going to replace the breaker and see if it helps. Thanks

 

[04fxdwgi]

Re: Engine Circuit Breaker

The breakers do go bad sometimes. That's why replacements are available. You should have continuity thru the breaker when button is pushed in and nothing with it out.

 

[glens5]

Re: Engine Circuit Breaker

I had the same thing happen a couple of years ago. The circuit breaker would trip and the motor would stall. The breaker would reset and the motor would restart. This happened four or five times in a row until the breaker finally wouldn't reset.
After being towed back to the dock I checked it out and found the 12V supply for the ignition shorted to the intake manifold. For what ever reason the was no protective loom around the wires.
My experience with these breakers is that they progressively become weaker the more times they trip. Whether that would cause it to open entirely is hard to say.

 

[Bondo]

Re: Engine Circuit Breaker

I had the same thing happen a couple of years ago. The circuit breaker would trip and the motor would stall. The breaker would reset and the motor would restart. This happened four or five times in a row until the breaker finally wouldn't reset.
After being towed back to the dock I checked it out and found the 12V supply for the ignition shorted to the intake manifold. For what ever reason the was no protective loom around the wires.
My experience with these breakers is that they progressively become weaker the more times they trip. Whether that would cause it to open entirely is hard to say.

Ayuh,.... Ya had a Dead Short,..... How is it the Breaker's fault,..??

Sounds like it was doin' it's Job, as designed,...

Donno if that might be part of cannonman's problem or not,...

 

[glens5]

Re: Engine Circuit Breaker

It was an intermittent dead short in my case. And yes, the breaker was definitely doing it's job.
In Cannonman's case he says the breaker is open now. The bimetallic strip seems to trip the breaker easier the more often it has been heated by an over current condition.
It was just a thought that his breaker possibly had failed altogether by the time he removed and tested it.

 

[Hdbikerman]

I've lost all power to my boat.... I was attempting to jump start it and poof everything went dead. My outdrive is now stuck in the down position and I have no clue on how to get power restored. Can ANYONE help me???? Please...

 

[GA_Boater]

I've lost all power to my boat.... I was attempting to jump start it and poof everything went dead. My outdrive is now stuck in the down position and I have no clue on how to get power restored. Can ANYONE help me???? Please...

Start a new thread instead of posting in a 7 year old and inactive thread. And please tell us what motor won't start.

Closed.