Weird Electrical Prob

[MetalDemon]

Hey guys gots a prob!
Mercruiser 260 r

Was out other day and after about an hour boat died. I remember hitting a small wave at about 30 mph then everything went black. I changed out a 20A ignition fuse on the panel and after that the engine was able to crank but would not start. I've checked for loose connections under the panel but everything looks good. As of right now boat has no power to any of the gauges and the engine cranks but won't start.

Only other thing of note is I changed out my alternator other week with a gm one... has not given me any troubles thou.

Thanks

 

[Bondo]

Re: Weird Electrical Prob

Ayuh,... The Igntion circuit is Dead,...
Dig out your Test Light, or Multi-meter,+ start chasin', 'n Checkin'...

 

[fat fanny]

Re: Weird Electrical Prob

On my ray there is a small fuse located where the harness from the main plug and all other electricals come together it's in a plag like the main connector for all the electrials maaybe try ther it's about the size of a m80 with small hose clamp dolding it sealed. might be worth a shot but do as boondo says afterwords only other option that comes to mind.

 

[MetalDemon]

Re: Weird Electrical Prob

Ok so was messing around with the boat and got some weird readings from the alternator. Dude at Autozone confirmed it was dead. I changed it out with an under warranty new rebuild one. All the gauges came back on and I was able to start the boat.... that is until I noticed the giant smoke in the back coming from the alternator.

I ended up pulling it out and I traded it back with 10 bucks for a brand new one. This time INSTANTLY after installing the new one I noticed the smoke building up! I didn't even have the boat on so quickly I pulled the alternator wires off.

I took the meter out and tested the 3 wires that go into the alternator; the orange one was like 12.5v, and the purple and red wire also showed 12.5v, purple wire showed nothing.

Now I'm no spark head (at all) but shouldn't the orange wire be the only one that has power (going into alternator?) Maybe there is a dead ground and its heading back to the alternator through the purple and red wire? I checked the wiring diagram the purple and red wire seem to charge from the circuit breaker then from the starter..... well I'm stumped anyway if you could help I got more details for the asking if it helps!

Thanks

 

[MetalDemon]

Re: Weird Electrical Prob

Bump for a poor electric noob

 

[MetalDemon]

Re: Weird Electrical Prob

Last bump before shop!

 

[Eric 3.7LX Alpha 1]

Re: Weird Electrical Prob

One of them wires to the alternator must be shorted out in order to be wiping out the new ones. You do know that the alternator has to be USCG approved, AKA marine rated? auto ones can have sparks come out the openings and ignite any vapors in the engine bay.

Check each wire on the alternator for continuity with ground and see if any have a short. What type/model of alternator are you using?

 

[MetalDemon]

Re: Weird Electrical Prob

Gots a 3 wire delco alternator
The purple and red wire is hot and the purple wire is not. The more I look at the diagram the more I think its correct.... but then why would it be smoking? Is it possible the solenoid switch is bad or something?

Thanks

 

[cr2k]

Re: Weird Electrical Prob

Purple wire is key switch power, always on all boats. Red is battery power and the orange is power to energize the alt. Are any of them hooked to a ground on the alt?

 

[MetalDemon]

Re: Weird Electrical Prob

The wires are on correct. The boat will run the way it is too, its just gonna start smoking after a bit. The only other thing I can think of is that the ignition fuse blew the first time the alt fried. That's on the yellow and red line.

Testing the starter solenoid there seems to be constant continuity between the yellow/red wire and the ground. Is that normal? Wouldn't that have the same effect as hooking a hot wire to the ground of the alt? I have the solenoid out right now and I'm not near the boat right now so I can't meter the ground wire to the alt.

 

[MetalDemon]

Re: Weird Electrical Prob

Well figured out that the solenoid is fine and it was all normal... so I guess I'll just start again at the basic problem.

Boat seems to start fine and is great now that a new alternator is in. Problem comes after a little bit when the alternator starts to smoke. I removed the front end plug and alternator still lightly smokes just having the battery connected.

Just looking at the four wires on the alt I see purple, purple/red, black, and orange. Orange is tested at around 12.5v, and so is the purple/red. Purple was 0v and I didn't bother to test the ground (I wish I did.)

What would cause the alternator to smoke when the battery is plugged in and the the circuit is complete?

Thanks