Section X. ENGINE MUFFLER, CYLINDER HEADS, AND VALVES
104. Description
The muffler is a one-piece unit and is screwed to the muffler pipe. Three cast-iron manifolds comprise
the intake and exhaust manifold system. A center manifold is bolted to the left and right bank manifolds. Eight
mushroom type valves, driven from the camshaft, are located in the cylinder blocks.
105. Muffler
b. Cleaning, Inspection, and Repair.
(1) Clean all parts in an approved cleaning solvent.
(2) Clean all rust from the piping with a wire brush.
(3) Inspect all parts for damage. Inspect all threads for stripping or other damage. Repair or replace as
necessary.
(4) Check muffler for holes or other damage. Repair or replace as necessary.
106. Manifolds
a. Description. There are three units in the manifold assembly; the right cylinder bank manifolding, the
left cylinder bank manifolding, and the center manifolding. All three assemblies contain both exhaust and intake
manifolding cast as a unit.
b. Removal.
(1) Remove the canopy (para. 68).
(2) Remove the cylinder head housing,shrouding, and heat deflectors (para.68).
(3) Disconnect carburetor fuel line (para.68), governor control rod (para. 68) and choke control (para.
(4) Remove the two nuts (6, fig. 26) and lockwashers (7) securing the left cylinder bank manifolding
(10). Remove the two nuts (6) and lockwashers (7) securing the right cylinder bank manifolding (10)
and remove the manifold assembly as a unit. Remove the manifold gaskets (13 and 14) from the
cylinder block.
c. Disassembly.
(1) Remove the muffler pipe from the center manifold (3, fig. 26).
(2) Remove the four nuts (2) and lockwashers (1) securing the left cylinder bank manifolding to the
center manifold (3) and remove the four nuts (2) and lockwashers (1) securing the right cylinder
bank manifolding (10) to the center manifold. Remove the four manifold gaskets (13 and 14) from
the left and right cylinder bank manifold studs.
(3) Remove the two bolts (16) and lockwashers (15) securing the carburetor (5) to the center manifold
and remove the carburetor. Remove the carburetor gasket (17).
d. Cleaning, Inspection, and Repair.
(1) Clean the outside of the manifolds with an approved cleaning solvent. Blow out the insides of the
manifolds with compressed air. Clean the mounting stud threads on the cylinder bank manifolds
with a wire brush.
(2) Check the machine gasket surfaces for warpage with a straightedge. Replace any manifolds with
warped or deeply pitted gasket surfaces.
(3) Inspect the manifolds and gasket surfaces for cracks or breakage. Replace any cracks or broken
manifolds.
e. Reassembly.
(1) Position a new carburetor gasket (17, fig. 26) on the center manifold. Position the carburetor (5) on
the center manifold (3) and secure with two lockwashers (15) and bolts (16).
(2) Position new gaskets (13 and 14) on the studs (11) of both the left and the right cylinder bank
manifolds (10). Position the cylinder bank manifolds on the center manifold and secure with eight
lockwashers (1) and nuts (2).
f. Installation.
(1) Position new gaskets (13 and 14) into both left and right cylinder bank ports.
AGO 6871A
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