Systems Operation

Usage:

Introduction

When the words "use again" are in the description, the specification given can be used to determine if a part can be used again. If the part is equal to or within the specification given, use the part again.

When the word "permissible" is in the description, the specification given is the "maximum or minimum" tolerance permitted before adjustment, repair and/or new parts are needed.

A comparison can be made between the measurements of a worn part and the specifications of a new part to find the amount of wear. A part that is worn can be safe to use if an estimate of the remainder of its service life is good. If a short service life is expected, replace the part.

Reference: See 3208 Marine Engine Attachments, SENR2133, for Specifications

Electrical System

Contactor Switch For Water Temperature

Water Temperature Contactor Switch

The contactor switch for water temperature is installed in the front cover for the engine. No adjustment to the temperature range of the contactor can be made. The element feels the temperature of the coolant and then operates the micro switch in the contactor when the coolant temperature is too high. The element must be in contact with the coolant to operate correctly. If the cause for the engine being too hot is because of low coolant level or no coolant, the contactor switch will not operate.

The contactor switch is connected to the fuel shutoff solenoid to stop the engine. The switch can also be connected to an alarm system. When the temperature of the coolant lowers to the operating range, the contactor switch opens automatically.

Pressure Switch

These type pressure switches are used for several purposes and are available with different specifications. They are used in the oil system and in the fuel system. One use of the switch is to open the circuit between the battery and the fuel shutoff solenoid after the oil pressure is below the pressure specifications of the switch. It also closes when the engine starts.

Another use of the switch is to close and activate the battery charging circuit when the pressure is above the pressure specification of the switch. It also disconnects the circuit when the engine is stopped.

Some switches of this type have three terminal connections. They are used to do two operations with one switch. They open one circuit and close another with a single switch.

Electrical Indicators And Sending Units

The electrical indicators and sending units are to operate in electrical balance. Because of this, the voltage and resistance ratings are important to get the correct indications on the indicators. See Attachment Specifications to determine which indicators and sending units can be used with each other.

Sending Unit And indicator For Water Temperature

Sending Unit For Water Temperature

The position of the pointer is changed by the amount of electrical current that flows through the indicator. The water temperature is felt by the bulb of the sending unit. A change in water temperature causes a change of resistance in the sending unit. A change in resistance in the sending unit changes the current flow through the indicator and changes the position of the pointer.

Sending Unit And Indicator For Oil Pressure

Oil Pressure Sending Unit

The position of the pointer is changed by the amount of electrical current that flows through the indicator. The oil pressure is felt by the sending unit for the oil pressure indicator. A change in oil pressure causes a change of resistance in the sending unit. A change in resistance in the sending unit changes the current flow through the indicator and changes the position of the pointer.

Wiring Diagrams

Starting And Charging System (Serial Number 01Z29478-UP)
(1) Key switch. (2) To indicators, etc. (3) To engine coolant loss sensor. (4) Circuit breaker 1. (5) Terminal strip. (6) To lights, etc. (7) ETR shutoff solenoid. (8) Circuit breaker 2. (9) "G" terminal. (10) "S" terminal. (11) "MTR" terminal. (12) "BAT" terminal. (13) Battery. (14) Starting motor. (15) Magnetic switch. (16) Alternator.

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NOTICE

Do not polarize alternator. Do not operate alternator without a battery connected to the system.

Starting And Charging System
(1) Off, Start Switch. (2) Ammeter. (3) Fuel shutoff solenoid. (4) Starter solenoid. (5) Alternator regulator. (6) Starting motor. (7) Pressure switch (normally open). (8) Alternator. (9) Battery. (10) Hourmeter.

Starting And Charging System
(1) Ammeter. (2) Key Switch. (3) Fuel shutoff solenoid. (4) 24V relay. (5) Regulator. (6) Starter solenoid. (7) Starter motor. (8) Battery. (9) Solenoid switch. (10) Shunt. (11) Terminal strip. (12) Alternator.

Optional Alarm Group (High Water Temperature And Low Oil Pressure Alarm System)
(1) Key switch. (2) 2 Amp fuse. (3) High water temperature switch. (4) Pressure switch. (5) Coolant loss sensor. (6) Toggle switch. (7) Battery. (8) Signal lights. (9) Horn.

NOTE: Toggle switch (6) must be in circuit if no other means of breaking the circuit is provided after engine is shut down or if sounding of alarm is objectionable at startup.

Optional Alarm Group (High Water Temperature And Low Oil Pressure Alarm System)
(1) Water temperature contactor. (2) Oil pressure switch (normally closed). (3) Battery. (4) Toggle switch. (5) Signal light. (6) Horn.

NOTE: Toggle switch (4) can be in the circuit for a way to turn off horn (6).

Remote Mounted Instrument Panel. (Engine Mounted Switch And Sender Single Instrument Panel Only)
(1) Key switch. (2) Engine oil pressure indicator. (3) Signal lights. (4) Water temperature indicator. (5) Gear oil pressure indicator. (6) Ammeter. (7) Terminal strip. (8) Engine oil pressure sending unit. (9) Water temperature sending unit. (10) Gear oil pressure sending unit.

Remote Mounted Instrument Panel (Shunt Equipped)
(1) Key switch. (2) Gear oil pressure indicator. (3) Ammeter. (4) Engine oil pressure indicator. (5) Water temperature indicator. (6) Shunt. (7) Terminal strip. (8) Engine oil pressure sending unit. (9) Water temperature sending unit. (10) Gear oil pressure sending unit.

Optional ETSO Engine Wiring
(1) Spring loaded stop switch. (2) ETSO shutoff solenoid. (3) To alternator ground. (4) To battery positive terminal. (5) To indicators. (6) To engine coolant loss sensor. (7) To starting motor magnetic switch. (8) To circuit breaker. (9) Key switch.

Tachometer Wiring Diagram With Speed Switch
(1) Magnetic pickup. (2) Tachometers. (3) Ground to engine. (4) Second tachometer circuit if required.

Tachometer Wiring Diagram For Tachometer Circuit Alone
(1) Magnetic pickup. (2) Tachometers. (3) Ground to engine. (4) Second tachometer circuit if required.