Cleaning, Inspection, And Repair; Cylinders; Gaskets And Gasket Surfaces - Johnson SKEE-HORSE 25-201R Service Manual

9-6
RETAINING
Figure 9-11
DRIFT _ _ _ --JIII
PIN
MOUNTING
Figure 9-12
Figure 9-13
SIDE
MARKED
"LOOSE"
UP
k. Remove connecting rod caps. Remove connecting rods from crank-
shaft.
1.
Reinstall matched caps on connecting rods.
m. Remove rings from pistons. DO NOT try to save the rings.
Install a complete set of new rings on every overhaul.
n. If necessary to remove connecting rods from pistons, remove
wrist pin retaining rings, using Truarc No. 1 pliers (Service Tool
#303857) (see Figure 9-11). Press out wrist pin to free piston
from connecting rod. See Figure 9-12. Piston wrist pin hole
marked "Loose" should be up when pressing out wrist pin to
prevent piston damage.
CLEANING, INSPECTION, AND REPAIR
When using trichlorethylene as a cleaning agent, use in a well
ventilated area at normal room temperatures, and under no
circumstances heated. Trichlorethylene vapors are poisonous.
CYLINDERS
a. Remove carbon from exhaust ports and cylinder heads. Carbon
accumulation in exhaust ports restricts flow of exhaust gases and
has a considerable effect on motor performance. Carefully scrape
carbon from cylinder heads and exhaust ports with scraper or
other suitable tool. Exhaust ports and all exhaust passages must
be free from carbon depOSits to insure maximum performance.
Clean compression relief valve and check for free action.
b. Check cylinder walls for excessive wear. Measure cylinder bore
for size and straightness by using an inside micrometer or dial
bore indicator. If wear is exceSSive, badly scored, replace cyl-
inders. Major portion of wear will be in port area and area cov-
ered by ring travel.
GASKETS AND GASKET SURFACES
a. Discard all gaskets, seals, and O-rings. Use only new gaskets and
seals in reassembly.
b. Remove all traces of dried cement and old gasket material, using
trichlorethylene or lacquer thinner.
c. Check gasket faces for flatness. Under certain conditions, gasket
faces may warp or spring, particularly where thin sections are
flanges are employed and are subject to temperature changes. To .
check for flatness, lay a sheet of No. 120 emery cloth on a surface
plate or piece of plate glass (see Figure 9-13). Place part to be
surfaced on emery cloth and move slowly back and forth several
times in a figure 8 motion, exerting evenly distributed, light pres-
)