Fuel Pump Module - Linhai T-Boss 550 Service Manual

CHAPTER 3 ENGINE
specified by the engine manufacturer to keep the
best fuel economy and proper engine performance:
- Use round wire-type gauge for an accurate
measure of gap on all used spark plugs.
- when gapping a spark plug only the side electrode
is moved. The center electrode must not be moved.
DO: When replacing spark plugs with new ones,
always use equivalent plugs with same heat range,
thread, size, etc....
DO: For installing spark plugs follow the following
steps:
1- make sure the cylinder head threads and spark
plug threads are clean. Make sure the spark plug
thread is free of dings and burrs. If necessary, use a
thread chaser and seat cleaning tool.
2- Make sure the spark plug gasket seat is clean,
then thread the gasket to fit flush against the gasket
seat. Tapered seat plugs do not require gaskets
3- Screw the spark plugs finger-tight into the cylinder
head. Then, use a torque wrench to tighten spark
plugs following manufacturer's recommendation.
Torque is different for various plug type & cylinder
head material.

3.5.8 Fuel Pump Module

3.5.8.1 Description and Working Principle
Fuel Pump Module supplies fuel to engine at system pressure. Fuel Pump Module is mounted
to fuel tank at top and supplies fuel to engine through hoses. Fuel Pump module consists of Fuel
Pump to generate the fuel flow and pressure regulator to regulate the fuel pressure.
When power is supplied to fuel pump, motor in pump assembly rotates the impeller. Impeller
in turn draws the fuel from strainer and pumps the flow to generate the system pressure.
Pressure Regulator is a diaphragm type mechanical device. Fuel flow from filter enters in the
inlet of pressure regulator. Pressure regulator regulates the fuel pressure at a set pressure by
releasing the excessive fuel flow to fuel tank.
3.5.8.2 Appearance
T-Boss550 SERVICE MANUAL20.0
misfire(higher required ignition voltage).
- Too narrow of a gap could affect idle stability.
- A flat gauge can't accurately measure the spark
plug on used plugs.
- Higher heat range plug(hotter plug) could lead to
pre-ignition & possible piston damage.
- Lower heat range (colder plug) could lead to cold
fouling & emission problem.
- If the thread is damage, it prevents a good heat
transform from the shell to the cylinder head.
- Do not use any type of anti-seize compound on
spark plug threads. Doing this will decrease the
amount of friction between the threads. The result of
the lowered friction is that when the spark plug is
torqued to the proper specification, the spark plug is
turned too far into the cylinder head. This increases
the likelihood of pulling or stripping the threads in the
cylinder head.
- Over-tightening of a spark plug can cause
stretching of the spark plug shell and could allow
blowby to pass thru the gasket seal between the
shell and insulator. Over-tightening also results in
extremely difficult removal.
CHAPTER 3 ENGINE PAGE. 3- 113