Snowmobile Yamaha Phazer PZ50 (2007-2008 year). Manual - part 71

7-30

FI

THROTTLE BODY

INJECTORS

Order

Job name/Part name

Q’ty

Remarks

Injector removal

Remove the parts in the order listed below.

1

Negative pressure hose

1

2

Idle adjusting screw

1

3

Throttle position sensor

1

4

Pressure regulator hose

1

5

Pressure regulator

1

6

Fuel strainer seat

1

7

Fuel strainer

1

8

Fuel rail

1

9

Injector

4

10

Throttle body heater hose

1

11

Air screw

2

12

Throttle body assembly

1

For installation, reverse the removal proce-
dure.

New

New

New

2

12

10

9

1

4

5

8

3

New

E

E

E

7

6

11

11

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THROTTLE BODY

INSPECTION

1. Inspect:

• Injectors

Damage 

→ Replace.

2. Inspect:

• Throttle body

Cracks/damage 

→ Replace the throttle body.

3. Check:

• Fuel passages

Obstructions 

→ Clean.

NOTE:

• Use a petroleum based solvent for cleaning.
• Blow out all passage with compressed air.

4. Check:

• Throttle body joints

Cracks/damage 

→ Replace.

PRESSURE REGULATOR OPERATION

1. Remove:

• Right side panel

Refer to “COWLINGS” in CHAPTER 3.

2. Inspect:

• Fuel pump and pressure regulator operation

Measurement steps:

• Connect the pressure gauge 1 and fuel pres-

sure adapter 2 onto the fuel injection pipe.

• Connect the mity vac to the pressure regulator

3.

• Start the engine.
• Measure the fuel pressure.

Pressure gauge:

90890-03153, YU-03153

Fuel pressure adapter:

90890-03176, YM-03176

Mity vac:

90890-06756, YS-42423

Fuel pressure:

300 kPa (3.0 kg/cm

2

, 42.7 psi)

2

1

3

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FI

THROTTLE BODY

• Use the mity vac set to adjust the fuel pressure

in relation to the vacuum pressure as described
below.

NOTE:

The vacuum pressure should not exceed 100 kPa
(760 mmHg).

Faulty 

→ Replace the pressure regulator.

Increase the vacuum pressure 

→ Fuel 

pressure is decreased
Decrease the vacuum pressure 

→ Fuel 

pressure is increased

INSPECTION AND ADJUSTMENT

NOTE:

Before adjusting the throttle position sensor, the
engine idling speed should be properly adjusted.

1. Inspect:

• Throttle position sensor

Checking steps:

• Disconnect the throttle position sensor coupler.
• Remove the throttle position sensor from the

throttle body.

• Connect the pocket tester (

Ω × 1k) to the throt-

tle position sensor.

• Measure the maximum throttle position sensor

resistance.
Out of specification 

→ Replace the throttle posi-

tion sensor.

Positive tester probe 

→ blue terminal 1 

Negative tester probe 

→ black/blue terminal 2 

Maximum throttle position sensor 
resistance:

4.0 ~ 6.0 k

Ω at 20 °C (68 °F)

(blue – black/blue)

L B/L Y

1

2

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FI

THROTTLE BODY

2. Adjust:

• Throttle position sensor angle

Adjusting steps:

• Connect the throttle position sensor coupler to

the wire harness.

• Connect the digital circuit tester to the throttle

position sensor.

• Measure the throttle position sensor voltage.
• Adjust the throttle position sensor angle so the

measured voltage is within the specified range.

• After adjusting the throttle position sensor

angle, tighten the throttle position sensor
screws.

Positive tester probe 

→ yellow terminal 1 

Negative tester probe 

→ black/blue terminal 2 

Digital circuit tester:

90890-03174

Throttle position sensor voltage:

0.63 ~ 0.73 V
(yellow – black/blue)

L B/L Y

1

2