Engine Speed Is Uneven; The Battery (Option) Is Not Charged - Yamaha EH63 Service Manual

ENGINE SPEED IS UNEVEN

ENGINE SPEED IS UNEVEN
1
No.
2
1 Check the fuel level.
2 Check if the fuel has deteriorated.
3
3 Check the spark plug for dirt and check the spark plug gap. Clean, adjust, or replace the spark plug.
4 Check the carburetor turn out and float height.
4
Check if there is air suction from the carburetor joint, gas-
5
ket, or throttle shaft.
5
Check if the slow or main passages, such as the main jet in
6
the carburetor, are clogged.
6
Measure the valve clearance.
7 (Refer to "ADJUSTING THE VALVE CLEARANCE" on
7
page 2-12.)
Check the valve face and valve seat for wear.
8
(Refer to "VALVES" on page 3-34.)
8
Check if there is seizure, wear, or damage on the piston,
piston ring, or cylinder.
9
9
(Refer to "PISTONS, CAMSHAFT, CRANKCASE, AND
CRANKSHAFT" on page 3-44.)
10

THE BATTERY (OPTION) IS NOT CHARGED

No.
1 Check the battery (option).
Check the stator coil assembly.
2 (Refer to "CHECKING THE STATOR COIL ASSEMBLY" on
page 5-11.)
Check the rectifier/regulator.
3 (Refer to "CHECKING THE RECTIFIER/REGULATOR" on
page 5-11.)
Check the entire charging system's wiring.
4
(Refer to "CIRCUIT DIAGRAM" on page 5-1.)
5 The charging system circuit is OK.
Checking steps
Checking steps
6-4
Possible remedy
Add the fuel if it is insufficient.
Replace the fuel.
Adjust or replace.
• Tighten the carburetor nuts securely.
• Replace the carburetor joint or gasket
with a new one.
Clean the parts.
Adjust the valve clearance.
Resurface or replace the valve face and
valve seat.
Rebore or replace.
Possible remedy
• Clean the battery terminals.
• Recharge or replace the battery.
Replace the stator coil assembly.
Replace the rectifier/regulator.
Properly connect or repair the charging
system's wiring.
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