TK 56433-5-MM-EN
35
accomplish this check with the tank right side up.
5.
Replace the switch if it is does not close in step 3
and does not open in step 4.
Checking the Float
The float is made of polypropylene foam. It is unlikely
that the float would fail unless it sticks inside the tank
so it cannot move.
1.
Verify the coolant level is above the float.
2.
Slowly drain coolant from the expansion tank and
watch the float. The float should drop with the
coolant level.
3.
If the float did not drop with the coolant level,
remove the expansion tank from the unit.
4.
Flip the expansion tank upside down and right side
up to see if the float moves inside the expansion
tank. Replace the expansion tank with a new one if
the float is stuck or does not move with the coolant
level.
Replacing the Coolant Level Switch
1.
Disconnect the wire harness connector from the
coolant level switch.
2.
Pull the coolant level switch straight up to remove
it from the tank. It may be necessary to use a small
pry bar or screwdriver. Take care to avoid damage
to the tank or switch.
3.
Place the new coolant level switch in the tank and
press it straight down until it snaps into place.
Check to make sure it is securely in place.
4.
Connect the wire harness connector to the coolant
level switch.
Engine Fuel System
The TK486V25X engine uses a mono-plunger and
distributor injection pump.
The components of the fuel system are:
•
Fuel tank
•
Fuel pre-strainer
•
Inlet strainer (in fuel transfer pump)
•
Priming pump
•
Fuel transfer pump
•
Fuel filter/water separator
•
Injection pump
•
Trochoid feed pump
•
Injection nozzles
The priming pump is used to manually draw fuel from
the tank up to the fuel transfer pump if the unit should
run out of fuel.
Operation
Fuel is drawn from the fuel tank and through the fuel
pre-strainer and inlet strainer by the fuel transfer
pump. The fuel transfer pump delivers fuel to the fuel
filter/water separator. Two orifices in the filter head
control the pressure in the fuel system by allowing a
certain amount of fuel to return to the tank. One orifice
is located in the center of the filter head. It bleeds off
water. The other orifice is located off-center on the filter
head. It bleeds off air. Filtered fuel passes through a
line from the outlet fitting on the filter base to the
injection pump.
The injection pump forces the fuel, at a very high
pressure, through the injection nozzles. The injection
nozzles atomize the fuel as it is injected directly into the
combustion chambers.
Injection pump leakage, injection nozzle overflow and
excess fuel from the fuel filter orifice are then all sent
back to the fuel tank in the return line.
Fuel Line Routing
The fuel lines from the fuel tank connect to the fittings
on the fuel filter. Do not change the factory routing of
the fuel lines from the fuel filter to the injection pump.
Maintenance
The injection pump and fuel transfer pump are
relatively trouble-free and if properly maintained will
usually not require major service repairs between
engine overhauls.
Contamination is the most common cause of fuel
system problems. Therefore, to ensure best operating
results, the fuel must be clean and fuel tanks must be
free of contaminants. Change the fuel filter/water
separator regularly, inspect/clean the fuel pre-strainer,
and clean the inlet strainer on the inlet side of the fuel
transfer pump.
IIm
mp
po
orrtta
an
ntt:: Do not open the fuel system unless
required.
N
No
otte
e:: The injection nozzles must be cleaned and tested
(and repaired if necessary) at least every 3,000
hours in accordance with EPA 40 CFR Part 89.
Normal conditions are considered to be the use
of clean high quality fuel, no used oil blending,
and regular maintenance of the fuel system
according to the Maintenance Inspection
Schedule. Refer to the TK482 and TK486
Overhaul Manual TK 50136 for injection nozzle
testing and repair procedures.
Whenever the fuel system is opened, take the following
precautions to prevent dirt from entering the system:
•
Cap all fuel lines.
•
Work in a relatively clean area whenever possible.
•
Complete the work in the shortest possible time.
