Engine schematic dgm

(return to Systems Descriptions of the Engine or 12-volt DC.)

(See NOTES related to Nevermore's configuration of engine circuits located after the right-hand part of the diagram later below.)

Engine electrical schematic diagram from Tartan manual

This schematic diagram appears on page Q.2 of the Engine Tech Manual. Page Q.2 has some prose across the top, and the diagrams below, in two columns. Herebelow, we have split the left and right columns of the one original diagram into two diagrams.

Also see the wiring diagram showing the same electrical functionality but also delineating how the engine and control panel are wired.

(Above) Left-hand side of page Q.2 of schematic in Tartan Tech Manual

(See NOTES related to Nevermore's configuration of engine circuits located after the the diagram below.)

(Above) Right-hand side of page Q.2 of schematic in Tartan Tech Manual

NOTES related to Nevermore's engine wiring configuration:

• See page Q.2 right-hand side for the SCHEMATIC INSERT for Westerbeke 50 engine's starter and glow-plugs. This diagram replaces the INSERT on the left-side schematic. Nevermore has 4 glow-plugs, not a pre-heater, and has a starter with integral solenoid; the starter's "minus" is grounded within the starter, which is bolted to the engine.

The 2 user-provided CktBrkrs (parts 45 & 46, discussed in written notes circle-B and circle-C), are located toward the back of the engine, and can be seen from the companionway area when viewed over the oil catch basin and under the engine. The two reset buttons are visible on a metal bracket, and the "10" and "40" amperage ratings are somewhat visible.

• Note circle-A relates to the need for two battery switching functions:
  • Switch SW1-1 12-V battery switch is an "on-off switch .... to disconnect the starter circuit from the battery in an emergency or when leaving the boat ...". This function is provided by Nevermore's two rotary main battery switches under the nav station seat.
  • Switch SW1-2 (under the "regulator" block on the diagram) is not wired. Without it, THE ALTERNATOR WILL BE DAMAGED if we switch off SW1-1.
    • We assume that Nevermore's SW1-2 is always made "ON" by the hard-wiring between the regulator and the "field" connection on the alternator. If this wire were replaced by the AFD contacts in the two main battery switches, we could alleviate this failure of the alternator. However, the high-amperage 12-volt contacts of main switch #2 would have to be rewired before the AFD switches are usable.
    • Another way to give the alternator protection function of SW1-2 is with a shunt (diode) which limits the alternator voltage when it has no load, i.e. when the 2 battery switches are OFF.
    • The way we get the altelrnator protection functionality that SW1-2 would give is with our rococco battery-switching SOPs.
• We think the optional SPLITTER (part 44) is not installed. We believe that Nevermore's schematic can be read with a metal connection between terminals "A" and "1" on the splitter on the schematic, with terminal "2" unwired.
  • Tech Manual page V.11 Service Bulletin #87 discusses adding the optional splitter. To account for voltage drop across the splitter, it says to "connect regulator wire directly to alternator output rather than to the regulator terminals". (Thom can't make sense of this on the schematic without the Svc Bull 22Sep07).
  • TODO: Per above note, (1) see if Svc Bull. #87 shows the "...regulator wire..." connection, and (2) see if we need to make a NOTE that changes the wiring at the alternator in the schematic above to agree with NOT having the splitter installed.

• FUEL PRESSURE SWITCH, item 11 on schematic:
  • The prose at top of page Q.2 diagram discusses the operation of this switch, how it functions in lieu of an "ignition switch" for starting the engine. Cranking the engine causes fuel pressure to build up, closing the switch, thus activating engine instrument readings; water over-temp and oil under-pressure alarms, and alternator output for battery charging.
  • This switch is discussed in the Nevermore Tech Manual page V.15, Service Bulletin #94. We think [but Thom doesn't have access to the book now (Fall'07)] this Bull. is moot, as it MAY discuss how to attach extra switches into the fuel-pressure fluid circuit, which we don't have. The same info is given in comment circle-G on right hand side of diagram.
    • TODO: read Bulletin #94 and see if above paragraph is right.
  • This switch is shown in the Parts List page 214 as item #33, attached to the Injection Pump item #41 via adaptor #32 and other little hardware; it's also shown on page 218 as item #6, seemingly the same configuration as the page 214 picture with all the same little fiddly parts.

• Written note circle-I isn't operative, since the control panel IS installed.