Service Manual

Exhaust Emission Control System
Carburetor
Thermo valve
EGR valve
Figure 55
1. Remove vacuum hose (green stripe) from carburetor
and connect a hand pump to the vacuum hose.
2. Plug nipple that vacuum hose was removed from.
3. Perform this test with the engine cold, then again
when hot. Apply vacuum to vacuum hose with the en-
gine idling.
When engine is cold
Coolant temperature 60
C (140F) or less:
(Green stripe)
Vacuum hose
Figure 56
Hand vacuum Normal condition
pump
Engine Vacuum
Vacuum applied No change Vacuum leak
Liquid Cooled
Gas Engine
Workman 3000/4000 Series Page 3 – 37 Liquid Cooled Gas Engine