Hobart Brothers 6910, Operation And Maintenance Manual With Illustrated Parts List

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(b) Control unit
The control unit (5, Fig. 3) is a box containing a compact assembly of solid state components.
It receives an AC signal from the magnetic pickup and senses speed changes in the engine.
It provides a voltage signal to the actuator which causes the actuator to move the fuel control
lever as required to maintain a predetermined engine speed. Its power is received from the
12-V DC battery system.
(c) Actuator
The actuator
(12, Fig. 3)
supplies the force needed to move and position the fuel lever as re-
quired to maintain a constant engine speed. The actuator is operated by a DC signal from
the control unit.
(2) Engine electrical system
Items in the 12-volt engine electrical system that are provided by Hobart Brothers are:
(a) A heavy-duty motor starter
(b) Alternator with voltage regulator
(c) Starting switch
(d) Wiring harness
(3) Engine protective devices
(a) High coolant temperature switch
A high coolant temperature switch is mounted in the back of the cylinder block to monitor the
coolant temperature. If the coolant temperature reaches 210 degrees F
(99 degrees C)
, this
normally closed switch opens and actuates the fuel valve solenoid which shuts down the en-
gine.
(b) Oil pressure switch
A diaphragm-type switch monitors the pressure in the lubricating oil system. It is mounted in
the side of the cylinder block
(18, Fig. 3) . If the pressure in the lube oil system falls to 10 psi
(69 kPa)
, this switch opens and actuates the fuel valve solenoid which shuts down the engine.
(4) Air cleaner
The diesel-engine air cleaner (Fig. 4) is a dry-cartridge type. It is equipped with a moisture elimi-
nator and a service indicator. The indicator functions to signal the operator when the cartridge
needs changing. A red cylindrical “flag”
(2) is forced upward in a glass enclosed viewing chamber
(1) when air pressure within the air cleaner housing drops below the outside air pressure. As the
cartridge becomes loaded with dirt and air pressure within the cleaner lessens, the “flag” gradu-
ally rises higher in the glass viewing chamber. When the “flag” reaches the top of the chamber, it
locks in that position to warn the operator that the cartridge must be changed. The “flag” is reset
(unlocked) by pushing the reset button (3) located on the bottom of the indicator.
NOTE: The service indicator is mounted on the engine control panel and connected to the air cleaner
by a rubber hose. The indicator flag is visible only when the engine is running, or when the flag is locked
in WARNING position.
(5) Exhaust system
The exhaust system consists of a special noise reducing muffler (2, Fig. 5) connected by a pipe
(1)
to the exhaust manifold. The tail pipe
(3)
directs exhaust and noise downward.
OM-2028
May 1/91 Revised 1-1
Page 9