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

ENGINE SPEED IS UNEVEN
6-4
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TROUBLESHOOTING
ENGINE SPEED IS UNEVEN
THE BATTERY (OPTION) IS NOT CHARGED
No. Checking steps Possible remedy
1 Check the fuel level. Add the fuel if it is insufficient.
2 Check if the fuel has deteriorated. Replace the fuel.
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. Adjust or replace.
5
Check if there is air suction from the carburetor joint, gas-
ket, or throttle shaft.
• Tighten the carburetor nuts securely.
• Replace the carburetor joint or gasket
with a new one.
6
Check if the slow or main passages, such as the main jet in
the carburetor, are clogged.
Clean the parts.
7
Measure the valve clearance.
(Refer to “ADJUSTING THE VALVE CLEARANCE” on
page 2-12.)
Adjust the valve clearance.
8
Check the valve face and valve seat for wear.
(Refer to “VALVES” on page 3-34.)
Resurface or replace the valve face and
valve seat.
9
Check if there is seizure, wear, or damage on the piston,
piston ring, or cylinder.
(Refer to “PISTONS, CAMSHAFT, CRANKCASE, AND
CRANKSHAFT” on page 3-44.)
Rebore or replace.
No. Checking steps Possible remedy
1 Check the battery (option).
• Clean the battery terminals.
• Recharge or replace the battery.
2
Check the stator coil assembly.
(Refer to “CHECKING THE STATOR COIL ASSEMBLY” on
page 5-11.)
Replace the stator coil assembly.
3
Check the rectifier/regulator.
(Refer to “CHECKING THE RECTIFIER/REGULATOR” on
page 5-11.)
Replace the rectifier/regulator.
4
Check the entire charging system’s wiring.
(Refer to “CIRCUIT DIAGRAM” on page 5-1.)
Properly connect or repair the charging
system’s wiring.
5 The charging system circuit is OK. —