Pistons, Rings, And Connecting Rods; Inspect Piston And Pin - Briggs & Stratton 030430 Service And Repair Manual

Pistons, Rings, and Connecting Rods

Remove Piston and Connecting Rod
1. Carefully remove any carbon or ridge at top of cylinder
bore to prevent ring breakage.
2. Remove rod bolts and connecting rod cap (A, Figure
69).
3. Push piston and rod assembly out through top of
cylinder.
Figure 69
Disassemble
1. Rotate pin retainer until one end is exposed in notch in
pin bore.
2. Remove the two retainer pins (A, Figure 70) with
needle nose pliers.
3. Slide out pin (B) from opposite side and remove
connecting rod from piston.
Figure 70
4. Using Piston Ring Expander #19340 (Figure 71),
remove rings one at a time. Not the order and
orientation of the rings before removal.
Figure 71
NOTE: Some oil control rings consist of two thin steel rails
and a spring expander. These must be removed by hand as
follows:
• Grasp one end of the upper steel rail and wind the rail
from the oil ring groove into the center ring groove.
Repeat into the top ring groove and then off the piston.
• Remove the spring expander, then remove the lower
steel rail.

Inspect Piston and Pin

1. Inspect piston for scoring, galling, or other damage.
Replace piston if necessary.
2. Using a dial caliper or plug gauge, measure the pin
bore diameter. Compare with reject dimensions listed
in Engine Specifications. If pin bore exceeds reject
dimensions, replace the piston.
3. Measure outside diameter of pin and compare to the
reject dimension listed in Engine Specifications. If pin
is smaller than the reject dimension, replace the pin.
4. Clean carbon from top ring groove.
5. Place NEW ring groove (Figure 72) and, using a feeler
gauge, measure space between ring and ring land.
Compare with reject dimensions listed in Engine
Specifications. If clearance is greater than shown, the
piston must be replace.
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