Breaker Trips everytime

The 40 amp breaker relay on the back of the engine is blowing everytime I fire the boat up. It happens after about 1 minute at idle. I have traced the amps and I am getting 40-41 amps going from the alternator to the breaker, then 40-41 amps from the breaker to the starter relay and then 30-35 going back to the battery. The battery is new, just got the alternator checked out and a new voltage regulator installed.

What would the 30-35 amps tell you coming from the battery? Also, where should the wire going to the alternator be running back to? Mine goes through this breaker and doesn't go through the ballast resistor first like I have seen in some drawings. Thanks in advance.

Jay

Pete,

I can't access the diagram. It says the page does not exist.

I am using a clamp that I got from one of our electrical engineers here at work. The alt is a 55 amp alt. I have a 40 amp breaker. Do I need to upsize the breaker to a 60 amp? I did test with an older spare battery and the amps went down but it was alot harder to start. Battery was probably pretty weak and was not fully charged. Had been sitting up in the front of the boat under the bow for a while.

I have only owned the boat since last September and this had happened twice where the breaker was tripped. Now it is happening all the time.

On the diagram that Tim posted, he shows a 50 amp breaker. What was the standard amp alternator. Is this an upgraded alternator that I have that is a 55 amp? The terminals at the relay look good.

Thanks Pete,

I went home at lunch and tested again to see which way the amps were going. Now the amps were a lot lower. Once I cranked the boat, the amps went out at around 300 then changed directions and were coming back in at about 23 back to the battery. We had been troubleshooting another issue last weekend with the fuel pump/line/anti siphon valve/carb, etc...and spent alot of time just trying to get the boat cranked. Once we finally got it cranked, after about 50 times trying, the breaker tripped. We never went out in the boat because of this. It just stayed at the dock all weekend. We got the fuel problem resolved and then this.

Would I be right in thinking that the boat could have run down the battery so much that it still had plenty of cranking amps but was low enough that the alternator was needing to give it 40 amps to try and charge back up the battery? And that now after I have run it for a while and it has sat that maybe it has charged up?

Thanks
Jay

Tim,

Thanks so much for the suggestion and the updated diagram. I will be upgrading this immediately. I see at skidim they only have a 50A or 60A breaker. Should I use one of those or where can I find a 55A?

Thanks
Jay

Hey,

I just put a 51amp alternator in place of the old 35amp and 40amp breaker that was in the boat. I also purchased the recommended wire harness and it came with a 50 amp breaker. I am also replacing the battery cables as I think they are old and full of voltage dropping corrosion.

Clew In