What a Dumba$$ I was ...

[Razzman]

Your charing and starting system shouldn't be protected anyway.

DB will have alts to fit any motor, but that one is probably a universal GM, one wire. Has a 2 1/2 ???? mounting ear and the support arm tang on the other side.

I talked with Mike there and he said it mounts the same as the Mando unit i have now. They are going to add the wiring neccessary for the tach pickup as well.

[Tequilasun]

Ha Ha, this reminds me of the first time I ever installed a CD player in my truck...I was 15 or so. I kept wiring it backward and frying the CD player (probably some internal fuse) and kept taking it back to Best Buy before I finally got it right!. I think I zapped 4 of them I'm much smarter now.

Razz, at least you got a new Alt out of the deal, and got to smell some really funny smelling smoke

[hoopykat]

Argh...tough luck Razzman...at least you didn't get hurt. Exploding batteries are no fun.

Mike

[Razzman]

Ha Ha, this reminds me of the first time I ever installed a CD player in my truck...I was 15 or so. I kept wiring it backward and frying the CD player (probably some internal fuse) and kept taking it back to Best Buy before I finally got it right!. I think I zapped 4 of them I'm much smarter now.

Razz, at least you got a new Alt out of the deal, and got to smell some really funny smelling smoke

Oh man did it stink! Still does! Mike at DB called me back and is having to do some additional research as there's a mystery purple/white wire connected to a pole on my alt that he has no clue what it is. Figures, my luck again!

[Razzman]

Argh...tough luck Razzman...at least you didn't get hurt. Exploding batteries are no fun.

Mike

Yeah especially since my face was 8" from the battery when i connected the lines!

[dogbert]

Sounds like SOP to me. Glad it wasn't more serious. At least this way you got a decent alternator that will actually charge your batteries.

[lee]

Mercrusier uses a 90 amp fuse on the starter for things like that.

[Razzman]

Mercrusier uses a 90 amp fuse on the starter for things like that.

Lee, you have any clue what a purple/white wire going to the altenator is for?

[chpthril]

Lee, you have any clue what a purple/white wire going to the altenator is for?

May be Choke if carburated?

[Razzman]

I had thought that as well but wasn't quite sure. The wire does go to the choke, but I also see it going to both ECM units and there's a lead that hangs by the coil not connected to anything. I don't see purple/white listed in any manuals or online anywhere. Oh well

[spharis]

The purple/white on my old alt was 12V for excitation. It ran from ignition to the engine misc ignition parts, my choke, and out to my alt. One wires do not need exciting as they sense through the charging cable.

What wiring do you have on your old alt? Your old alt had the tach pickup there? Mine was elsewhere.

Here is a picture of my old alternator.



The purple is the excitor, the orange is the charge, and the black is a case/circuit ground. If you go to a 1-wire, all that gets canned. Here is the new one.




The big purple is my charge cable.

[Razzman]

OK so what happens to all the other wires on a one wire conversion? Here's what DB sent me to help identify and below that is configuration.

[spharis]

They all go away.

The switching sensing and charging is all done through the one wire. The case gets ground through the mount. Did you trace out that purple/white wire yet? Check to see if it ties in to other switched wires, at the choke is a good spot, or across those two lugs (the two purple wires); if you get conitnuity there, then those can be moved to other switched source wiring in the rear of the engine. All the purple wiring in my boat is ignition switched 12V. Have a multimeter to check continuity? The trio ties into internal diodes, so maybe a switched component is using the alt as circuit protection?

It doesn't look like your tach pickup is connected there, although I think my tach pickup is blue/white......I can't remember now, but it is not on the alt.

[spharis]

Crap, Razz....I just re-read your post above where the purple/white goes to your choke. That is just a switched power wire, and could just as easily come off the ignition. It is probably also in the ECM for some of the ignition components. The choke has to have 12V to start warming the choke coil when the key is on; this is why it also runs to other components. Everything on that circuit has current when the key is in the on position. It doesn't need to by tied to RPM or charging state, just the key.

I would look into just getting a one-wire, pulling all the stuff you don't need anymore, and calling it done. Where does the solid purple switched wire run? If it is also ignition switched.

Also that dusconnected lead you have, you might want to be sure you have it capped. It is hot when the ignition is switched on.

[Razzman]

Well i know the purple/white does go to the choke and i see it going into the ecm ignition modules as well. The only switched component i can see it going is the choke. So what happens to the wires you eliminated? They just hang there?