Briggs & Stratton Vanguard 10V300, Repair Manual

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2. To verify cleanliness, lightly hone bore using a
suitable valve guide hone and then scrub with a valve
guide cleaning brush to remove any dirt or debris.
3. Measure the inside diameter using an inside ball
micrometer or plug gauge. Replace the cylinder head
if the measurement is 0.220 inches (5.592 mm) or
more.
Valve Seats
1. Inspect valve seats for cracking, chipping or burning.
Replace cylinder head if any of these conditions are
found or if either valve seat is loose.
Valves
1. Replace the valve if bent or if there is evidence of
burning or cracking.
2. Inspect the end of the valve stem for pitting or uneven
wear. Replace the valve if either of these conditions
are found.
3. Inspect the valve stem retainer groove for burrs,
damage or excessive wear. Remove burrs with a fine
tooth file if found.
4. Polish the valve stem with fine emery cloth or steel
wool to remove carbon buildup.
5. See Figure 55. Measure the top, center and bottom
of the intake valve stem using an outside micrometer.
Replace the intake valve if any measurement
is 0.209 inches (5.319 mm) or less.
6. Measure the top, center and bottom of the exhaust
valve stem. Replace the exhaust valve if any
measurement is 0.208 inches (5.278 mm) or less.
7. Hold each valve against a worn wire wheel in a
bench grinder to remove all carbon deposits from the
valve head and face, but exercise caution to avoid
removing any metal material.
8. Inspect intake valve face and seat. If only minimal
wear is found, lap the valve face and seat as follows:
A. Obtain fine Valve Lapping Compound (Part No.
94150).
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56
B. Apply lapping compound sparingly around the
entire valve face and valve seat.
C. Lightly lubricate the valve guide and valve stem
with clean engine oil.
D. See A of Figure 56. From the bottom of the
cylinder head, insert the valve stem into the valve
guide.
E. Push on bottom of valve until it contacts the valve
seat.
F. Obtain the Valve Lapping Tool (Part No. 19258).
G. See B of Figure 56. Attach suction cup at end
of tool to valve head. Holding shank of tool
between the palms of both hands, oscillate the
Not for
Reproduction