Troubleshooting; Engine Does Not Start - Yamaha EH63 Service Manual

ENGINE DOES NOT START

No.
Check the engine oil level.
1
(Refer to "ENGINE OIL LEVEL" on page 2-5.)
2 Check the fuel level.
3 Check if the fuel has deteriorated.
Check the spark plugs.
4
(Refer to "SPARK PLUGS" on page 2-3.)
Check the ignition spark gap.
5 (Refer to "CHECKING THE IGNITION SPARK GAP" on
page 5-6.)
Check the ignition coil.
6 (Refer to "CHECKING THE IGNITION COIL (TCI UNIT,
PRIMARY) RESISTANCE" on page 5-7.)
7 Check the carburetor for clogged passages or fuel overflow. Clean.
Check the compression pressure.
8 (Refer to "MEASURING THE COMPRESSION PRES-
SURE" on page 3-1.)
Measure the valve clearance.
9 (Refer to "ADJUSTING THE VALVE CLEARANCE" on
page 2-12.)
Check the valve face and valve seat for wear.
10
(Refer to "VALVES" on page 3-34.)
Check if the marks on the crankshaft and camshaft are
aligned.
11
(Refer to "INSTALLING THE VALVE LIFTERS AND CAM-
SHAFT" on page 3-53.)
Check if there is seizure, wear, or damage on the piston,
piston ring, or cylinder.
12
(Refer to "PISTONS, CAMSHAFT, CRANKCASE, AND
CRANKSHAFT" on page 3-44.)

TROUBLESHOOTING

Checking steps
6-1
Possible remedy
Add the oil if it is insufficient.
Add the fuel if it is insufficient.
Replace the fuel.
Re-gap or replace the spark plug.
If the ignition spark gap is OK, the igni-
tion system is OK.
Replace the ignition coil.
Too high:
Decarbonize the combustion chamber if
there is carbon deposits.
Too low:
Next checking steps.
Adjust the valve clearance.
Resurface or replace the valve face and
valve seat.
Correct.
Rebore or replace.
1
2
3
4
5
6
7
8
9
10