CYLINDER HEAD VALVES,OUIDES AND SPRINGS
(Refer to Figure M-3)
Removal
Steam clean engine before doing any cylinder block (13). Using a valve spring
disassembly or service work. compressor, inset
A, compress the valve
Close the fuel tank shut off valve and
disconnect the fuel line at the carburetor.
Disconnect the choke and throttle connec-
tions at the carburetor. Disconnect gover-
nor linkage and remove carburetor
(1) and
baffle (2).
Remove and disassemble breather (25-31),
cylinder head bolts (4). Remove the engine
air deflector (5), cylinder baffle (6) and
head baffles (7) . Remove the generator ad-
justing bracket (8) .
Remove the spark plug (9), wire (10),
cylinder head (11) and gasket (12) from
springs
(17) and remove the valve retainer
locks
(15). Remove the valve retainers (16),
springs, spring retainers (18), and valves
(19).
To remove valve guides (20), drive them
down into the tappet chamber and carefully
break them off. Drive the balance of the
guides down and remove.
IAUT/0/1 Be
very careful not to damage the cylinder
block when breaking off the guides. The
exhaust valve seat (21) can be removed by
using a seat removing tool, refer to inset
B. Remove tappet adjusting screws {22)
if
they are to be replaced.
Inspection
Remove all carbon from head, bore and valve guides. Blow out with compressed air. Refer
to Pages M-6 and M-7 for inspection of valves, seats.
Inspect the tappet adjusting screws for wear and replace
if worn.
Check the cylinder head for warpage by using a face plate. The head should make contact at
all gasket surfaces.
If it doesn't, replace cylinder head.
Installation
Drive new valve guides (20) in place un-
til they are flush with the bottom of the
valve chamber. The guides must be reamed
to size after installing, refer to Specifica-
tion Section for proper dimension. Install
exhaust seat (21) by cooling it in dry ice
and drive into the block.
Install valves (19), spring retainers (18)
springs
(17) and valve retainers (16). Com-
press valve springs and install locks (15).
Install new head gasket (12) after soaking
it in oil. Install head (11) baffles (6) and
(7), air deflector (5) generator bracket (8)
and head bolts (4).
Tighten head bolts to proper torque. Back
of the bolts and retorque to proper torque.
Ref er to Specifications Section.
Clean, regap and install spark plug (9).
Adjust tappets, refer to tappet adjustment.
Install the breather assembly in the follow-
ing order, stud (24) gasket (25), plate (26)
with small drilled hole down, reed valve
(27) and baffle (28),
Clean and lubricate filter (29) with engine
oil and install. Install outer gasket (30),
seal (31), cover (32) washer (33), and nut
(34) . Tighten the nut only enough to make a
good seal.
Install baffle (2) carburetor (1) and gas-
ket. Connect throttle and choke connections.
Connect governor linkage and fuel line. Open
fuel tank shutoff.
TAPPET ADJUSTMENTS
Hand crank the engine to set piston at the DC mark of the compres-
sion stroke, inset C. Outward pressure will be
felt when the thumb is
placed over the spark plug opening when the piston is coming up on
the compression stroke. A lighter pressure is also
felt on the exhaust
stroke. DO NOT CONFUSE THE TWO, Refer to Specification Section
for proper
tappet clearance. Using a feeler gauge, set tappets ,inset D.
M-4
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