Ignition Circuit breaker
 

The other day we went out for late night cruise when all of a sudden everything went dead. If I remember correctly, I had my courtesy lights, nav lights, windshield defog, and possibly my docking lights (not sure of this one) on when everything went dead and the engine cut out. My first thoughts were the big red reset button by the carburetor, but that wasn’t the cause. Next I checked the circuit breakers on the side panel at the driver’s feet and found the one marked “Ign” had popped. I reset it, and all was good.

I have looked at the wiring diagrams on the "Original Mariah Manuals and Supplements Fourm" but cannot find anything that indicates the wiring and amperage for the circuit breakers. Based on my experience it would seem that everything runs through the “ign” breaker and is overloading it or the breaker is to low an amperage or is going weak, but without the proper wiring diagram I am at a loss as to which it would be. Any advice someone can offer would be appreciated.

Thanks

Re: Ignition Circuit breaker
 

To test the breaker your going to have to run at least 50 amp thru it (probably more like 60) to get it to pop if it is good. It's going to be hard to accomplish that though in a test senario. I'd probably replace it and then reinact the failure again and see what happens.
You can start ohming out wiring , to see if you have a grounding short somewhere , but I'd just spend the 15.00 and replace the breaker first. They do get weak over time.
Electrical can be a real PITA!!
JMO :)

Larry

Re: Ignition Circuit breaker
 

Finally got around to checking my breakers. I was surprised to see that the main "ign" breaker in the breaker panel is only 15 amp. This seems rather small because it is the main breaker in the 9 breaker panel. All the other circuits feed through this main breaker. Does anyone know whether this is the right amperage or should it be a higher amperage breaker? Your comments are appreciated.

Thanks

Re: Ignition Circuit breaker
 

If you are talking about the ignition fuse it should be a 20amp according to our 5.7 electrical service manual. I believe the main circuit breaker mounted on top of the engine is 50amps.

As a silver contributor, you have access to the Mercruiser 5.7 (GM5057) electrical systems pdf file in the "Service, Repair & Operating Manuals" section.

Re: Ignition Circuit breaker
 

Thanks Mikey. I have checked all the online material and cannot find anything that gives the amperage or wiring diagram for the breaker panel on my boat.
I am talking about the breaker panel on the side panel just forward of the stereo console as seen in the attached picture.

The amperages on the various breakers are as follows:
Dck lts 15
Lts 10
Acc 15
Defog 20
Horn 10
Ign 15
Blwr 10
Bilge 5
Wiper 5

All the breakers get their power supply daisy chained from the ign breaker so this would lead me to believe that a PO may have switched about the breakers without paying attention to the amperages. If anyone can shed some light on this it would be appreciated?

Thanks

Re: Ignition Circuit breaker
 

I know this is an old post, but this is exactly what happened to us today. Finally got fuel issues under control and we are cruising like never before today. The engine just shuts off. Push the red circuit breaker button and that does not help.

I looked for an ignition circuit breaker, but I couldn't find one on my boat. I do not see a box like you have pictured.

Can any one help me diagnose the problem?

Michael

2003 Mariah Barchetta
4.3L V6

Re: Ignition Circuit breaker
 

A couple of things to check:

Check the 50 amp breaker on top of the engine if that's not it replace the square white fuse assembly that is on the positive side of the starter. Disconnect the battery before replacing.

Re: Ignition Circuit breaker
 

I do not remember the white box, but I will look for it tonight. Interesting thing that I did see was the solenoid mounted to the starter (not the slave solenoid) seemed to be loose and did not appear to be mounted securely in it's metal case. I thought that could not be it because the starter would operate with the slave jumped. That is the thing that was odd to me. I could get the engine to turn over if I jumped the slave solenoid. Could that solenoid have failed? From your extremely helpful diagram (thanks!!!), it looks like I could test that by applying power to the yel/red terminal.

Does this make sense?

Oh - I remembered something else. The low oil pressure audible warning did not come on, no matter how long I left the switch on.


Where do I get one of those white boxes? Even if that is not it, looks like a nice spare to have.

Thanks!
Michael

Re: Ignition Circuit breaker
 

Your thoughts on testing the circuit should be correct. The fuse box is available at any Mercruiser dealer and places like iboats.com

If you look at the top of this forum you should find a 'sticky' covering the troubleshooting of your ignition system.

Re: Ignition Circuit breaker
 

great write up - after reading it, it seems the only logical guess is the ignition switch. I can get the starter to crank with the short of the slave solenoid.

How does the low oil pressure alarm fit into all this? Is it driven off continuity from the ignition switch? Why is it not activating?

Just thought of something - none of the gauges worked either. Sump, blower and lights worked, but anything driven off ignition did not work - must be switch?

Where do I get an ignition switch for a 1993 Barchetta?

Thanks for your quick replies.