(1) Suspend thermostat in a container of
water so that it does not touch the bottom of the
adjustment, maintain given idle
(2) Heat water and check temperature with a
speed with throttle screw.
thermometer. The thermostat valve should start to open
at about 160 deg. F and should be fully open at 180 deg.
Refer to paragraphs 6-69a.(1) and
(3) If the thermostat opens before the
c. Installation. Reverse procedures in paragraph 6-
water temperature reaches 160 deg. F or does not open
69a.(1) and (2). Carburetor mounting gasket may be
until after the water temperature reaches 180 deg. F, it
reused if it is not damaged.
should be replaced.
c. Inspection. Inspect adapter for deterioration.
Inspect elbow (housing) for cracks and thread for
(1) Disconnect carburetor air duct, throttle,
d. Installation. Reverse procedure in a. above,
choke, and governor linkages at carburetor. Remove
using a new gasket between the elbow and the cylinder
gas line from fuel pump to carburetor.
head. Make sure split in adapter aligns with bypass hole
(2) Remove two nuts and washers and
remove carburetor and gasket.
6-66. FUEL SYSTEM.
(3) Remove tube to check valve at manifold
6-67. AIR CLEANER.
and remove check valve and its adapter from the
a. Removal. Loosen clamp securing air cleaner to
air cleaner bracket and lift off air cleaner.
(4) Remove two nuts and washers, exhaust
elbow flange and gasket.
(5) Remove six nuts and washers and remove
manifold and gasket. Discard gaskets removed.
Don't tip air cleaner, to avoid spilling
b. Cleaning. Soak manifold in SD long enough to
soften crusted deposits. Clean machined surface with
flat bladed scraper. Clean bores of passages with
scraper and wire brush. Dry with clean cloths.
(1) Unscrew wing bolt, remove cover and
c. Inspection. Inspect for warpage at machined
element, and pour off old oil from air cleaner body.
surface with straight edge. Replace manifold if warpage
(2) Wash all parts of air cleaner in SD, and
is bad enough to be possible source of leaks. Check for
cracks in casting.
(3) Saturate mesh of element in OE. Permit
d. Installation. Using new gaskets, reverse a.
excess to drain.
(4) Reinstall body of air cleaner, fill to OIL
LEVEL line with OE, and install cover and element and
c. Installation. Reverse procedure in a. above.
(1) With fuel in tank, disconnect fuel line at
carburetor and install fuel pressure gauge.
(1) Connect vacuum gauge to intake manifold
(2) Crank engine for twenty to thirty seconds
and tachometer to engine. Start and warm up engine.
and note gauge reading. Pressure between 1-1/2 psi
(2) With throttle screw, adjust engine idle to
and 2-1/4 psi is required.
450 to 500 rpm.
(3) Adjust idle mixture screw to setting giving
(1) Shut off fuel supply at tank and disconnect
the highest possible vacuum reading.
both fuel lines at fuel pump