Yamaha EF1000iS Service Manual

2-9
MUFFLER
12
3
4
SVU2150
MUFFLER
w
The engine and muffler will be very hot
after the engine has been run.
Avoid touching the engine and muffler
while they are still hot with any part of your
body or clothing during inspection or
repair.
1. Remove:
9Muffler
Refer to “MUFFLER” in CHAPTER 3.
9Muffler band 1
9Muffler cap 2
9Muffler screen 3
9Spark arrester 4
2. Decarbonize:
9Muffler
Tap on the muffler in the area shown in
the illustration to loosen carbon
buildup, and then shake it out of the
end of the...

2-10
VALVE CLEARANCE ADJUSTMENT
4
123
VALVE CLEARANCE ADJUSTMENT
1. Remove:
9Cover 3
9Side cover 2
9Rear cover
9Front cover
Refer to “COVERS”.
9Carburetor
Refer to “CARBURETOR” in CHAP-
TER 3.
9Cylinder air shroud
Refer to “MUFFLER” in CHAPTER 3.
2. Remove:
9Spark plug cap 1
9Spark plug 2
9Breather hose 3
9Cylinder head cover 4
3. Gently operate the starter rope to bring
the piston to the top-dead-center of its
compression stroke (when the screwdriv-
er inserted into the spark plug hole reach-
es the...

2-11
VALVE CLEARANCE ADJUSTMENT
1
2
3
5. Adjust:
9Valve clearance
Adjustment steps:
•Loosen the locknut 1.
•Turn the adjuster 2in or out to obtain the
proper clearance.
•Tighten the locknut 3.
use hexagonal wrench.
6. Install:
9Cylinder head cover gasket
9Cylinder head cover
9Breather hose
9Spark plug
9Spark plug cap
9Front cover
9Rear cover
9Side cover
9Side cover 2
9Side cover 3
INSP
ADJ
Adjuster Valve clearance
Turn in Decrease
Turn out Increase
Locknut:
4 Nm (0.4 m · kg, 2.9 ft · lb)
Cylinder head...

2-12
COMPRESSION PRESSURE
12
COMPRESSION PRESSURE
NOTE:
Measure the compression after checking and
adjusting the valve clearance.
1. Warm up the engine for several minutes.
2. Remove:
9Spark plug
3. Remove:
9Cover
4. Connect:
9Compression gauge 1
9Adapter 2
5. Measure:
9Compression
To measure the compression, pull the
recoil starter until the needle stops ris-
ing on the compression gauge.
w
To prevent sparking when cranking the
engine, ground the high-tension cord. 
Testing steps (below minimum level):...

2-13
COMPRESSION PRESSURE/
RATED ENGINE SPEED/BREATHER HOSE
1
1
a
1
Testing steps (above maximum level):
9Check the cylinder head, valve surfaces,
and piston crown for carbon deposits.
6. Install:
•Spark plug
RATED ENGINE SPEED
1. Remove:
9Cover
2. Connect:
9Inductive tachometer 1
3. Inspect:
9
Rated engine speed
Specified engine speed →OK
Out of specification →Refer to “TROU-
BLESHOOTING” in CHAPTER 3.
Inspection steps:
9Operate the engine (with no load).
9Turn economy switch 1to “OFF” a.
9Measure the...

2-14
SPARK PLUG
1
2
a
ELECTRICAL
SPARK PLUG
w
Inspect and adjust the areas around the
cylinder head after the engine has cooled
down completely.
cC
Before removing the spark plug, use com-
pressed air to clean the cylinder head
cover to prevent dirt from falling into the
engine.
1. Remove:
9Cover
2. Remove:
9Spark plug cap
9Spark plug
3. Inspect:
9Electrode 1
Wear/damage →Replace.
9Insulator color 2
4. Measure:
9Spark plug gap a
Use a wire gauge or thickness gauge.
Out of specification →Regap.
If...

2-15
SPARK PLUG/ENGINE SWITCH/
ECONOMY SWITCH/PILOT LIGHT
a
b
b 1
a
1
a
1
5. Tighten:
•Spark plug
NOTE:
To prevent thread damage, finger tighten a
the spark plug before tightening it to the spec-
ified torque b.
ENGINE SWITCH
1. Check:
9Engine switch 1
Checking steps:
9Set the engine switch 1to “ON” a.
9Start the engine.
9Check that the engine stops when the
switch is set to “STOP” b.
ECONOMY SWITCH
1. Check:
9Economy switch 1
Checking steps:
9Set the economy switch 1to “ON” a.
9Start the engine.
9Turn...

2-16
RECEPTACLE/DC CIRCUIT BREAKER
2
1
1
a
b
RECEPTACLE
1. Check:
9AC receptacles (7.5 A) 1
9DC receptacle (12V, 8 A) 2
Cracks/damage →Replace.
Poor connection →Correct.
DC CIRCUIT BREAKER
1. Check:
9DC circuit breaker
Checking steps:
9Press the reset button 1to the position of
“RESET” a.
9Connect the pocket tester (DC 20 V).
9Start the engine.
9Set the economy switch to “OFF”.
9Measure the DC voltage.
9Set the reset button to “OFF” b.
Voltage is zero →OK
NOTE:
If the restet bottn pup out (“OFF”) again,...

INSPADJ
7VV10-02  02.10.4 10:38 AM  Page 17
______ -lt~tl  

ENG
3-1
CONTROL BOX
ENGINE
CONTROL BOX
1
2
Order Job name Q’ty Remarks
Control box removalRemove the parts in the order listed 
below.
Front cover and rear coverRefer to “COVERS” section in CHAPTER 2.
1 Tapping screw 4
2 Control box assembly 1
For installation, reverse the removal
procedure.
1
2
3
4
5
7VV10-03  02.10.4 10:38 AM  Page 1