4-28 RESTRICTION INDICATOR (CONT)
Do not operate heater in enclosed space. Adequate ventilation is re-
quired to prevent buildup of exhaust fumes which can be toxic in con-
Wear approved ear protection equipment within 25 feet (7.6 meters) of
operating heater. Failure to do so may result in impairment or loss of
Start engine. Recheck restriction indicator window (1).
If red is visible, shut down engine and replace restric-
tion indicator. Press button (2) on new restriction
Touching hot engine surfaces can cause severe burns. Protect skin
when making following test.
Restart engine. Using wadded rag, flat tool, or
other blocking material, restrict flow of air into
intake tube (4) and observe restriction indicator.
If red is not visible, shut down engine and per-
form following steps.
Unscrew from safety filter (3).
Unscrew from pipe elbow (5).