Generac 4451 Manual De Usuario

• Move engine CHOKE knob to “Full Choke” position.

•  To start engine, press and hold the Start/Run/Stop switch in

the “Start” position.  The engine will crank and attempt to start.

When the engine starts, release the switch to the run position.

•  When the engine starts, move choke knob to “1/2 Choke” position until

the engine runs smoothly and then to “Run” position. If engine falters,

move choke knob to “1/2 Choke” position until the engine runs

smoothly and then to “Run” position.

•  Shut off all loads, then unplug the electrical loads from

generator panel receptacles.  Never start or stop the engine

with electrical devices plugged in and turned on.

•  Turn “Off” the Idle Control switch (if on).
•  Let engine run at no-load for several minutes to stabilize the

internal temperatures of engine and generator.

•  Move Start/Run/Stop switch to “Off” position.
•  Close fuel valve.

: Do not overload the generator.  Also, do not

overload individual panel receptacles.  These outlets are protected

against overload with push-to-reset-type circuit breakers.  If

amperage rating of any circuit breaker is exceeded, that breaker

opens and electrical output to that receptacle is lost.  Read “Don’t

Overload the Generator” on page 9 carefully.

This feature is designed to greatly improve fuel economy.  When

this switch is turned 

“On,”

the engine will only run at its normal

fast governed engine speed when electrical load is connected.

When the load is removed, the engine will run at a reduced speed

of 2100 RPM.  With the switch 

“Off,”

the engine runs at the

normal fast engine speed all the time. 

Under certain weather conditions (temperatures below 40° F (4°

C) and a high dew point), the engine may experience icing of the

carburetor and/or the crankcase breather system.  To eliminate

this problem, this generator engine is fitted with a winter/summer

valve.  this directs hot air into the carburetor during cold weather

operation.  Always make sure the winter/summer valve is in the

correct location relative to the weather conditions.

The engine is equipped with a low oil pressure sensor that shuts

down the engine automatically when the oil pressure drops below

10 psi. If the engine shuts down by itself and the fuel tank has

enough gasoline, check engine oil level.

A delay built into the low oil shutdown system allows oil pressure

to build during starting. The delay allows the engine to run for

about 10 seconds before sensing oil pressure.

If the system senses low oil pressure during operation, the engine

shuts down.

If you try to restart the engine within 10 seconds after it shuts

down, the engine may NOT start. The system needs 5 to 10

seconds to reset.

If you do restart the engine after such a shutdown and have not

corrected the low oil pressure, the engine runs for about 10

seconds as described above and then stops.

1

0C5729

1

ASSEMBLY, CRANKCASE HOUSING
WITH SLEEVE

2

0E9843

1

SEAL, 38 I.D. CRANKSHAFT 

3

090388

3

SCREW, TAPTITE M6-1.0 X 12 BP

4

0C5372

1

ASSEMBLY, BREATHER

5

0C3005

1

GASKET, BREATHER COVER

6

0E3372B

1

SEPARATOR, OIL BREATHER

7

0D8067A

1

ASSEMBLY, HEAD #1

8

071983

4

RETAINER, PISTON PIN 20

9

0D5269

1

ROCKER, COVER 

10

043790A

1

BARBED EL 90 3/8NPT X 3/8

11

0E2950

2

PISTON, LC (GT-990)

0E2985

2

PISTON, HC (GT-760)

12

021533

2

SET, PISTON RING 90MM

13

0E1466

2

PIN PISTON 

14

0D4041

1

ASSEMBLY, CAMSHAFT & GEAR 

15

0D4788

2

PLUG STD PIPE 3/8 STEEL SQ HD

16

093064

1

ASSEMBLY, OIL FILL CAP

17

0C2977

1

GASKET, CRANK CASE 

18

0C5943

1

SEAL, OIL PASSAGE 

19

0E4357E

1

ASSEMBLY, CRANKSHAFT 
HORIZONTAL DIRECT DRIVE
(GT-990)

0E4356E

1

ASSEMBLY, CRANKSHAFT 
HORIZONTAL DIRECT DRIVE
(GT-760)

20

0E3223

2

ASSEMBLY, CONNECTING ROD 
(GT-990)

0E3222

2

ASSEMBLY, CONNECTING ROD 
(GT-760)

21

0D2157

2

SCREW SHC M6-1.0 X 50 G8.8

22

0E6098

1

SCREEN, OIL PICKUP

23

0D4123A

1

ASSEMBLY, OIL PUMP

24

078699E

2

SLEEVE, SEAMED DOWEL 10 DIA.

25

0C3011

2

COVER, OIL RELIEF

26

0C3009

2

SPRING, OIL RELIEF 

27

0C3010

2

BALL, 1/2D OIL RELIEF 

28

093873

2

WASHER, LOCK RIB M6

29

0C5315

1

GEROTOR, OUTER

30

0C5998

1

CLAMP, OIL TUBE

31

0D4497

1

PLUG-CRANKCASE GOVERNOR 
BORE

32

0C3971E

1

ASSEMBLY, DIPSTICK WITH 
HANDLE

33

0D3745

1

TUBE, DIPSTICK

34

0C3027

3

O-RING, OIL CLR

35

0E9842

1

SEAL, 42 I.D. CRANKSHAFT 

36

0C5731

1

ASSEMBLY, HOUSING COVER 
WITH SLEEVE

37

0C3006

10

SCREW, HHFC M10-1.5 X 55

38

080318

8

SCREW HHFC M6-1.0 X 25

39

0C8808

2

HOOK, LIFTING

40

0C2981C

1

ROCKER, COVER 

41

0C2979

2

GASKET, VALVE COVER 

42

086515

8

KEEPER, VALVE SPRING

43

0D2274

4

RETAINER, VALVE SPRING 

44

0D3867

4

SPRING, VALVE 

45

078672

2

SEAL, VALVE STEM D7

46

0C5371

4

WASHER, VALVE SPRING

47

072694

4

STUD, ROCKER ARM PIVOT

48

0C3027

2

O-RING, 3/8" X 1/2"

49

0D5313

4

ROCKER ARM

50

0D3998

4

NUT, HEX M8-1.0 GB YELLOW 
CHROME

51

0D6024

2

PLATE, PUSH ROD GUIDE

52

0C2976

12

SCREW HHFC M8-1.25 X 65

53

086516

2

VALVE, EXHAUST

54

0C2229

2

VALVE, INTAKE

55

083897

4

TAPPET, SOLID

56

0D8067B

1

ASSEMBLY, HEAD #2

57

0D9853D

4

PUSHROD 147

58

0C2978

2

GASKET, HEAD

59

0D6008

1

KIT GEAR COVER

60

0D4010

1

KIT GASKET

61

0D6007

1

KIT PISTON & RINGS

62

0D4012

1

KIT BREATHER ASSEMBLY

63

0D8675A

1

KIT HEAD ASSEMBLY CYLINDER 1

64

0D8675B

1

KIT HEAD ASSEMBLY CYLINDER 2

65

0D4015

1

KIT OIL RELIEF

Item 59 (Kit) includes items 3, 30, 35, 65
Item 60 (Kit) includes items 2, 5, 17, 18, 34, 35, 40, 57, 139, 153.
Item 61 (Kit) includes items 8, 11, 12, 13
Item 62 (Kit) includes items 4, 5, 6
Item 63 (Kit) includes items 7, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 

53, 54, 57, 58

Item 64 (Kit) includes items 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53,

54, 56, 57, 58

Item 65 (Kit) includes items 25, 26, 27