MAINTENANCE PROCEDURES
4. Start
the
engine and
let
it
warm up for approxi-
mately
3-5
minutes. Do not adjust the carburetor
when the engine is cold. The adjustments should
be made
at
the temperatures
that
the trimmer
will
be used. Allow the engine to idle. If neces-
sary, re-adjust the idle speed to keep the engine
from stalling
(3000-3500
RPM on the TC400,
3000-4500 on the TC300)
CAUTION:
DO NOT RUN THE TRIMMER
INDOORS WITHOUT ADEQUATE VENTILA-
TION. EXHAUST FUMES ARE POISONOUS
AND COULD BE DEADLY
IF
INHALED.
5.
With' the engine idling, slowly turn the low speed
screw
clockwise and note the position
at
which
the engine begins to slow down. Now turn
the
screw counterclockwise and again note the posi-
tion when the engine speed is reduced. Set the
screw at
a
point midway between these two
positions.
6.
Hold
the
throttle wide open and follow the same
procedure to set the high speed screw.
7.
Re-check the idle adjustment.
8.
Install
the
air cleaner cover.
TROUBLESHOOTING AND
TEST PROCEDURES
Generally, all gasoline-powered products require
some form of service or repair during their lifetime.
The amount of time and expense involved
in
repair-
ing
a
product can be greatly impacted by the amount
of time required to initially determine the cause of
the difficulty. Therefore,
it
is recommended to make
these preliminary checks before proceeding to sec-
ondary troubleshooting procedures.
Preliminary Checks
1. Check for ignition:
a. Check the start/stop switch position
2.
Check the spark plug: (refer to specifications.
Page
3)
a.
To ensure
the
correct type
b. For damage to the insulator
c. For excessive carbon or burnt electrodes
d. For the correct gap
e.
Check for spark (refer to page
8)
3. Check
the
fuel supply:
a. Check the choke position
b. Check the condition of the fuel, for freshness,
cleanliness, and proper mixture
4. Check the air cleaner: (refer to page
4)
a. For loose or damaged mounting screws
b. For dirty filter elements
c. For excessive oil
in
the foam element
5.
Check cylinder compression (refer to page
7)
Testing
Cylinder Compression
A compression test of the engine can provide vital
information on the general condition of the working
parts within the engine. This test
will
indicate
a
worn
cylinder, piston, or ring and generally determine
whether
the engine is sound or if
it
should be
replaced,.
Compression
Test
Procedure
1.
Install the compression gauge into
the
spark plug
hole. :IMPORTANT: Be certain that no more than
a
1/2”
of
the gauge is threaded into the cylinder as
damage to the piston may result (Fig. 14).
Figure 14
Compression testing
2.
Pull
the
starter rope several times to obtain the
highest possible compression reading.
3. If the compression reading is below
100
psi
(689
kPa),
cylinder,
piston, or ring damage should be
suspected If
so
damaged, a
new
engine
short-
block /should be installed.
7
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