Service Manual

When engine is hot

Coolant temperature 80C (176F) or higher:

Hand vacuum

p pump

Normal condition

Engine Vacuum

4 kPa (30 mm Hg,

1.2 in. Hg) of

vacuum applied

No change Vacuum is

maintained

20 kPa (150 mm

Hg, 6 in. Hg) of

vacuum applied

Idling becomes

slightly unstable

EGR Valve Inspection

1. Remove EGR valve and inspect for sticking, carbon

deposits, etc. Clean with a suitable solvent if necessary

so valve seats correctly

2. Connect a hand vacuum pump to EGR valve.

3. Apply 67 kPa (500 mm Hg, 20 in. Hg) of vacuum and

check to make sure vacuum is maintained.

4. Apply a vacuum and check passage of air by blowing

through one side of EGR passage.

Figure 57

Vacuum Passage of air

4 kPa (30 mm Hg, 1.2 in. Hg) Air is not blown out

or less

2.0 kPa (150 mm Hg, 6 in. Hg) Air is blown out

or more

Installation

1. Use a new gasket and tighten to a torque of 9 Nm (0.9

kgm, 0.6 ft

–lb).

Liquid Cooled Gas Engine

Page 3

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Workman 3000/4000 Series