I’m installing a new alternator and I’m not sure what the four wires are for that come from the engine block area. The four wires are red, white, brown and black. The wires are visible near or on top of the alternator. These wires usually get connected to the internal alternator regulator or the external regulator. I have a Westerbeke W-27a engine.
Also, does anyone know what the red cables grouped with labels A1, B1, and B2? These connections are just inside the engine access panel in the cabin and are near the heat exchanger on a W-27.
Do you have oil pressure and water temp audio alarms on your engine? Do you have engine panel with oil and water gauges (Admiral Panel), or just oil and temp lights(Captain Panel)? You can download on internet a W27 engine wiring diagram that maybe of help to tell you what different colour wires are for.
When I got my boat 6 yrs ago, the oil and water alarms didn’t work, so I spent some time studying the wiring diagram. As it turned out, the wires to the alarm buzzer were incorrectly connected. But I can tell you that some wires at the alternator, and buzzer, that do not connected to anything, it depends on which engine panel your boat has.
Some wires are coated in Westerbeke red paint and need to be scrapped to reveal true colour.
And some have changed colour with age, blue to green for example. On my wiring diagram there is a separate sub-diagram for Balmer 100 amp alternator.
Well, I’ve sure learned a lot with the new alternator install. It took much longer than I anticipated, but it’s finally done. I really didn’t want to do the install, but I couldn’t find a single diesel mechanic who was interested in the work, and I called on 4 or 5 mechanics.
Balmar telephone technical support was pretty good, but email responses were slow and way too brief to be much help.
I also learned that owners don’t always keep there same color scheme going when splicing wires. I think they used whatever color they had available.
The bundle of positive wire connections turned out to be a old school Traditional Diode Isolator, (Battery Splitter) which is used to split the alternator charging (A1 in the picture) between Battery Bank 1 (B1) and Bank 2 (B2).
