Fuel System - Yanmar 1GM User Manual

32
VOLTAGE OUTPUT TEST
CHAPTER TWO
35A ALTERNATOR
55A ALTERNATOR
If the reading varies or if no reading is obtained, check for
poor connections or damaged wiring.
6. Tum the key switch ON. Run the engine from idle up
to 2,500 rpm and note the voltmeter reading. If the volt-
meter does not indicate 14.2-14.8 volts, remove the alter-
nator and have it bench tested by a dealership or qualified
specialist.
Alternator Current Output Test
This test checks the current output of the alternator. All
wires connected to the alternator for normal operation
must be connected. Refer to Figure 7 for this procedure.
1. Check the alternator drive belt tension. See Chapter
Three.
2. Disconnect the negative battery cable.
3. Disconnect the wire from the BAT terminal on the al-
ternator.
4. Connect the positive lead of a 0-100 amp DC ammeter
to the BAT terminal and the negative lead to the discon-
nected wire.
5. Reconnect the negative battery cable.
6. Make sure the engine control is in the stop position.
7. Tum on all accessories and crank the engine for 15-20
seconds to remove any surface charge from the battery.
8. Tum off all accessories.
9. Connect a tachometer to the engine. Connect a carbon
pile load device to the battery terminals.
10. Start the engine and run at 2,500 rpm. Adjust the car-
bon pile to obtain maximum alternator output. The amme-
ter should read the rated amperage according to the
alternator model identified on the data plate on the alter-
nator (Figure 8). Model LR135 alternators should pro-
duce 35 amps, and model LRl55 alternators should
produce 55 amps.
FUEL SYSTEM
Refer to Chapter Seven for a description of fuel system
operation. A diagram of a typical fuel system is shown in
Figure 9.
Be aware that diesel fuel injection systems require clean
fuel that meets the fuel requirements specified by the en-
gine manufacturer. Many fuel problems are a result of
contaminated fuel or fuel not approved by the engine
manufacturer. Refer to Chapter Three.
NOTE
Engine components outside the fuel system
can also cause some ofthe following engine
symptoms. Be sure to check other engine
components that can also cause the symp-
toms.