That yellow wire from the motorola alternator

[Baltimore Sailor]

You know, the thin one with the blade plug on the end? Should that be plugged into a gray wire that goes to the positive terminal on the coil?

When I took the wires off I labeled them, but after I found I'd labeled both wires from the electronic ignition as "coil +", I now doubt everything I've done.

So -- that thin yellow wire: to the positive terminal? And also -- what is that wire for?

Thanks!

[Don Moyer]

It sounds like the field flashing wire which energizes the fields of the alternator to bring it on line each time you start the engine. Do not confuse this wire with the output from the alternator. The output wire is normally an 8 or 10 gauge orange wire.

Don

[olebiker]

It sounds like the field flashing wire which energizes the fields of the alternator to bring it on line each time you start the engine. Do not confuse this wire with the output from the alternator. The output wire is normally an 8 or 10 gauge orange wire.

Don

Don, does that 'yellow wire' connect inside the casting to the two wires that connect to the alternator housing on opposite sides of the alternator? If the flashing wire lost continuity inside the casting (some kind of epoxy it appears), could a person connect the flashing wire from the + side of the coil to either of the other two wires that are connected to the outside of the alternator? My alternator quit and I bought a new of from you, which works great, but want to use the old one as a back up if I can get it to work.
Thanks,
gary

[Don Moyer]

Gary,

Sorry, but I can't tell what wires you are referring to from your report.
To save time, I suggest you take your old alternator in to a local
automotive starter/alternator shop and ask them to identify the field
flashing connection for you.

Don

[Chip Hindes]

Do we all make the same mistakes :-) ?

I had "help" when I pulled my motor for rebuild, which help in fact was excellent except that the wires from the alternator (only) didn't get labelled when they were pulled.

After everthing was back in and hooked up, I identified a loose wire with a large ring terminal which I measured at 12V and which I suspected was the output wire, but hooking this one up has done nothing so far. It's not 10 or 8 gauge, maybe 12. I did not smell the telltale smell of frying semiconductors, so I don't believe the alternator diodes are fried yet.

The alternator also has a dangling, shielded male spade terminal connector with no visable mate anywhere in the engine compartment. So to re-ask the first question, is the sensing or excitor wire or whatever else it is called go to the coil+ or can the fact that it is dangling in space be OK? The schematic Don provided shows only one wire to the alternator output, no hookup to the coil+ other than the ignition switch. The previous owner told me he was having battery trouble; is it possible his troupble was actually a fried alternator? It's a standard looking Motorola, has been painted at least three different colors over its lifetime and could well be original on the '74 boat.

Colors are of no help as the whole wiring harness is a veritable rat's nest of wrong colors, unknown circuits, dangling wires not hooked up to anything and even (I swear) a couple wire nuts holding stuff together. Rewiring the entire motor is on the list but right now after the full motor rebuild I'd just like to get my new (to me) boat out on the water for the first time in our abbreviated Northeast sailing season.

Guess I could try tracing the orange (if it is orange) wire from the ignition switch and see where that ends up. From the rest of the wiring on the boat it could well be powering the fan in the head. Never saw such a mess of wiring.

BTW, my new motor is running great, but I'm afraid to take it any distance from the slip since it appears it's running on the battery only. The shore power extension cord for the battery charger isn't long enough :-)

[Chip Hindes]

All is well. When I returned to the boat ready to pull the alternator for testing, I noticed on the counter next to the sink a piece of wire about 15" long, ring terminal one end labelled "coil", female spade connector other tend labelled "alternator". In my own handwriting.

Hooked it up, fired the motor, 14 volts at the terminal.

[Kelly]

Hello Chip,

Thanks for the history of your hair pulling. All is well that ends well and your found wire "labeled in your own handwriting" will remind many of their own lapses (myself included). Always a humbling experience...

Happy sailing.

Kelly