Intermittent electrical none start no Accessories power, power returns by its self

[allan.munroe]

I have a 2003 4.3 L mercury that will not crank and all electric accessories are also dead, battery good. Accessories, lights , blower etc. if switch is left on will come on intermittently even if key is in off position and I am not near the boat. Is it possible the the main breaker is the problem as it seams to be sticking?

 

[allan.munroe]

Is it possible that a bad main circuit breaker can prevent engine from cranking , not even a click and at the same time prevent all other electrical accessories to not operate. Can this happen intermittently. If a leave the lights switch on they will come on by themself after a period of time even if I’m not there.
The main breaker seams to be sticking when I try to push it. There is no actual “click”. Is there anything else that could cause this problem?

 

[Scott06]

Yes main circuit breaker would cut off power to key switch , but it would click if it was reset after tripping. easy to measure if you have power coming out of it .
most likely would start with your positive and negative battery cables check both ends are clean and tight

 

[alldodge]

Sounds like there is corrosion
Start by removing and cleaning battery cables and make them shinny metal on both ends, and don't for get both ends of the ground

Pull the 10 pin engine connector and clean those pins

 

[allan.munroe]

Sounds like there is corrosion
Start by removing and cleaning battery cables and make them shinny metal on both ends, and don't for get both ends of the ground

Pull the 10 pin engine connector and clean those pins

Thanks but not sure where or what is the 10 pin engine connector. I must had toggled the running lights to the on position. They were definitely not on when I looked last night but was up three hr later and they were. I know it sounds crazy but is a fact.

 

[alldodge]

The 10 pin is the large connector on top and rear side of motor

 

[nola mike]

Is it possible that a bad main circuit breaker can prevent engine from cranking , not even a click and at the same time prevent all other electrical accessories to not operate. Can this happen intermittently...Is there anything else that could cause this problem?

Possible, but many more likely causes. All accessories are wired separately from ignition and gauges so should work with key off. First step is make sure you're getting 12v to the main fuse panel, red wire normally. I'd bet you have corrosion at that point, especially if you have glass fuses in there. That would cause problems with both gauges and accessories. Cannon plug also a common fail point as AD said.

 

[dingbat]

Intermittent power problems are easy to track as long as your systematic and don't make any assumption with your troubleshooting.

You always start at the source (battery) with power problems. If you have power there, move to the next device, ie main circuit breaker.
Circuit breakers are thermal devices that are prone to failures over time. If it doesn't "latch" when reset all beats are off. Check power to and from the main breaker while the problem is present.

From there, move to the input (wire) to the main fuse box, etc.