TM 5-3655-210-12
1. Screw
2. Rotor
3. Feeler gage
Figure 4-9. Checking for correct breaker point gap.
Test or Inspection
Malfunction
Corrective Action
Test or Inspection
Corrective Action
4. ENGINE BACKFIRES
3. ENGINE KNOCKS
Step 1. Listen for irregular engine performance and
Step 1. Check to see if oil level is low.
check exhaust for excessive black smoke
Refill.
indicating gasoline mixture being too lean.
Step 2. Check panel to see if engine is operating under
Adjust the carburetor by turning idle
adjusting screw (1, fig. 4-12) as needed to
heavy load at low speed.
Adjust the governor, paragraph 4-27.
get smoothest idle possible.
Step 3. Check for the running spark advance mark
Step 2. Listen for sticking inlet valves (missing engine)
being advanced too far by removing screws (1,
(chattering noise) and check for possible
fig. 4-10) and screen (2). Observe timing mark
backfire.
Adjust valves as follows:
(1, fig. 4-11) Time the magneto, paragraph 4-40.
Step 4. Check for a loose flywheel by removing the
a. Turn the crankshaft over by hand until
screen (fig. 4-10) and checking for a loose nut
the lifter (6, fig. 4-13) that is to be adjusted is
or key out of position.
at its lowest position.
Place key in position in slot and tighten
b. Insert 0.012 in. (.0305cm) feeler gage (5)
flywheel nut (2, fig. 4-11).
between the valve stem (8) and lifter screw
(7). Hold lifter (6) with wrench, and turn lifter
Malfunction
adjusting screw into or out of the lifter with
4-13
