Ignition breaker keeps popping
 

This just started on the last trip. The starboard ignition breaker pops when the key is turned to the "Run" position not "Start" within 1-3 seconds. The breaker will reset in a minute or two. If I pass straight thru the start up sequence it may or may not click the starter over. The Port side is working fine. I have since replaced both of the ignition switches with new ones and swapped the ignition breaker from port to starboard and starboard to port and the starboard still pops. It has become an issue slowly in the last few outings that the starboard side would not crank or rather engage the starter. At first I thought maybe it was the shifter lever neutral switch. But wiggling lever never really helped it just finally engage the starter when I kept trying to start it. I'm a little embarrassed by this part but I ran the starboard fuel tank empty on the last trip and after refueling it took 8 -10 cranking sequences to restart the engine. I waited between starts but could the starter have been the initial problem and repeated start attempts "cooked" it? The starter is only 1-1/2 years old. Or are there other things I should look at? Thanks in advance.

IF you are talking about the red 50 amp push button breaker.
Your alternator may be shorted out.
Remove the big red wire from the back of the alternator and see if the breaker stays in.

^^^^^^^^^^^ Check your engine grounds and open up the plugs in the mercruiser harness and inspect for corrosion. Starter solenoid may be shorting also.

The breaker in question is the black rubber one right next to the ignition key. But I may try the alternator wire thing. And its not the starter solenoid I swapped out the starters today. I guess all the little connectors are next. I hate chasing electrical gremlins.

That's the 20 amp ignition breaker, so this can be many things. Any of your gauges for that side and any or the engine powered items (fuel pump, coil, relays, alternator, etc). Don't know what motor, but if it has an electric fuel pump listen for it to power up, then if EFI pull the relays one at a time.

Its a 2000 Fountain w/500 EFIs. I have pulled the wires from the alternator and there is no change. I did notice that the "alarm" or "start signal" comes on the Port but not the Starboard side. Where are the relays that you are referring to?

With the alarm not coming on, pull the purple wire off, it should be behind the helm. If the alarm shorts out it will also pop the breaker. The relays are on top the motor, they look like small square cubs about 1.5 inch square

I have alot of purple wires. Do you mean the dark red with a white stripe? But now that you have mentioned it the fuel pump is not coming on. But before I start pulling pumps is there a breaker or fuse for the pump?

look for a connector with a grey/black cap on it back by the distributor, pull the cap and there should be three fuses , one is the fp fuse, pretty sure its the same one as the 502 mpi

Yes, the purple wire comes from the key switch to every, gauge, alarm, ECM, ALT everything that gets turned on. The alarm is small, about the size of a quarter (round) and about a 1/2 thick and is usually black. Alarm has one purple wire and the other side is a Tan/Blue wire. The Red/White is not what your looking for.

So I found the alarms, tan wire, purple wires etc. If I understand you correctly. Pull the purple from ignition switch? There is a purple and purple and wire connected together at each switch. I diconnected them and nothing. I swapped the alarms and no change. I found two 20 amp relays under the dash and swapped them. No change. I disconned all the wire to the alternater and no change. Found one fuse inline on the red wire to the Mercathode. Its good. I cant see much behind the motor but appears to only be connectors. I cant make out any relays. Still searching for the problem. Could it be the fuel pump itself?

No, need to find the purple wire on the alarm and only pull the wire off of the alarm

Disconnecting the purple wire off the ignition switch keeps everything from turning ON

In the pic note that the purple wire goes to every gauge. If any one of the gauges is pulling to much current then it will pop the breaker. You mentioned you could not hear the fuel pump come on, nor hear the 2 beeps when key is turned to ON. This shows a fuse where you have a breaker.


https://cimg4.ibsrv.net/gimg/www.off...5ac40a771d.jpg


This is what the relay should look like

https://cimg4.ibsrv.net/gimg/www.off...c132a08536.jpg

https://cimg0.ibsrv.net/gimg/www.off...86c8a418ea.gif
Id disconnect the cannon plug to isolate the engine from the helm, the relays are a pita to find they are amounted on the bracket where the ecm is mounted

Sorry, but if the cannon plug is disconnected from the motor then there will be no power to the key or the breaker

This is going in a bit deeper
The main power relay (MPR) is turned on by the purple wire when the key is tuned ON. The purple wire goes from the engine harness to the EFI harness (both on the motor) in a connector which changes it from purple to a pink wire. The fuel pump is turned on by the ECM applying a ground to the fuel pump relay coil side, this happens after the MPR energizing and turning the ECM ON.

ya I didnt think that one through.......

Your saying you cut the purple wire coming off the key and the breaker still popped?

Alldodge: I found the starboard side alarm, The quarter size round one. It was surrounded by the wire bundle. Thin purple wire going in tan and purple coming out. I cut the thin purple wire and turned the key on and it still popped the breaker. I appreciate your patience in this trouble shooting even if we don't figure it out I owe you at least one beer. There is something to be said about people that know electrical issues. Ford

Look on top of the motor for a flat connector. Your looking for the Tan/Blue and the Purple wires. In the pic, the left is 496 and the right is the prior V8 connector, both show these wires. You may even have 2 connects, but in any case these supply main power from the key, to the ECM harness. If this connector is disconnected, then we will know if the issue is on the motor or between motor and helm.

https://cimg3.ibsrv.net/gimg/www.off...0e51bdab16.jpg

Yep, at the dash, the kill switch or the engine connector to the dash.
The purple wire goes from the key to the kill switch and then to each gauge and back to the engine. So anywhere along, if there is a place where the insulation rubbed thru or one of the gauges could be shorting out.

Could remove the purple off ever gauge and if it stops, then start putting it back on one by one, or just remove one at a time and test

Another thought, is if the breaker has gone bad, but don't think this is the issue because your not hearing the fuel pump turn on

I was afraid of that. I have swapped out the breaker with the port side amd back again. So I would make the breaker "good". Guess I will start with the gauges. So again I am assuming, if I start at one side of the dash and go to the other side one gauge at a time that I only have to remove the purple wire connector because everything is in series?

Yes
Also when removing the purple wire, the terminal lug should stay connected to the other gauges. If you find there are 2 lugs on the one stud, both purple, they need to both be removed but kept together during testing, or the circuit will be disconnected to the other gauges

So I finally got time to chase this electrical issue and maybe I found something im not sure. The purple wire runs across the back of every gauge in series on the starboard side of the dash panel. When it gets to the last gauge in the series which is the Oil Pressure gauge a 6-8 inch purple wire comes off the oil pressure gauge to a female post connector and stops. The port side has a purple and white stripe wire connecting the gauges in series. So the Purple/white wire after the Oil Pressure gauge connects to a very thin pink wire that is in a sleeve of wires that appear to go to my compass. There is a larger blue wire that connects to a thin white wire and a large black wire connected to a thin black wire. Those thin wires Pink, black and white are in a sleeve with other thin wires that are just cut flush. A light brown, light blue and light green wire. Is the large Purple wire supposed to just end into a open connector or is it supposed to connect to something. I wish I paid my subscription fee so I could post a picture.

you can post pic's now even if a non-paying member. So,post it up. :)

I would think this to go to the alarm horn but you said you cut that wire

I would say yes, so long as it is sealed off there is no issue, and can be used to connect another item later

May have found something. Disconnected the purple wire from the tach and the breaker did not pop. However the fuel pump and the buzzer under the dash are still not beeping or running and it will not crank. Still looking for answer.

Most gauges are daisy chained, so there should be 2 purple on each gauge unless it is teed off at another location