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Valves are not identical. Make sure the valve marked
“EX” or “X” is installed in the exhaust valve location, and
the valve marked “I” is installed in the intake valve
location. If the valves are unmarked, the nonmagnetic
valve is installed in the exhaust valve location.
Valve Adjustment
Clearance between the valve stem and lifter must be set
to the recommended specifications when the engine is
cold (see page 40). Check these clearances with the
piston T.D.C. on the compression stroke. Grind end of
valve stem with a valve grinder, or use a “V” block to hold
the valve square on grinding wheel, grinding to the proper
.004" to .008” (.101 - .203 mm) clearance.
NOTE
Some emissionized engines use intake valve stem seals
to maintain proper oil control and emission compliance,
They must be replaced if the valve has been removed.
Valve Installation
1.
To reinstall valves, position valve caps and spring in
the valve compartment.
2.
Install valves in guides with valve marked “I” in the
intake port. The valve stem must pass through the
spring. The valve spring cap should sit around the
valve lifter exposed end.
Use extreme care when servicing
any springs. Wear the appropriate
safety equipment. These springs may be highly
compressed and could fly out with considerable
force. Failure to do so may result in death or
serious injury.
3.
Use a valve spring compressor to compress the
valve spring.
4.
Position the valve spring cap onto the valve stem
and release valve spring tension to lock cap in
place.
Seal Cutter
3/64"
(1.19 mm)
Seat
31
o
46
o
Wrong
Right
Face
Valve Lifters
It is a good practice not to interchange lifters, even
though they are identical, once a wear pattern has been
established.
Oversize Valve Guides
Valve guides are permanently installed in the cylinder. If
they become worn excessively, they can be reamed
oversized to accommodate a 1/32'’ (.79 mm) over size
valve stem.
1.
Ream guides with a straight shanked hand reamer
or low speed drill press.
2.
Refer to Table of Specifications to determine
correct oversize dimension.
Reamers are available through your Tecumseh parts
suppliers.
3.
See Tool Section for correct part numbers.
4.
After oversizing valve guides the seats must be
recut to align with the valve guides.
11-2
WARNING
