SRM-420ES, SRM-420TES
T410S, B410S
T410TS, B410TS
44
ENGINE
44
6-4 Testing crankcase and cylinder sealing
1. Remove muffler cover, air cleaner cover, cyl-
inder cover, starter assembly and innner covers.
Remove carburetor, insulator plates and cable
holder (Refer to “4-12 Replacing purge bulb”).
2. To seal intake port, install pressure rubber plug
897826-16131 (A) and pressure plate 897827-
16131 (B) and tighten M5 bolts or screws (C) of
12 - 16 mm (0.5 - 0.6 in) length as shown.
3. Loosen three muffl er bolts. To seal exhaust port,
insert pressure rubber plug 91041 (D) between
cylinder exhaust port and muffl er gasket (E), until it
bottoms. Tighten the muffl er bolts.
4. Connect pressure / vacuum tester 91139 (F) or
91149 to pulse pipe (G).
5. Apply pressure approx. 0.05 MPa (0.5 kgf/cm
2
) (7
psi) by pressure / vacuum tester and leave for 30
seconds.
6. If the reading drops, leakage may occur.
7. Leakage may occur from crankcase seam or oil
seal. Use soapy water to locate leakage.
8. Then, apply negative pressure approx. 0.03
MPa (0.3 kgf/cm
2
) (4 psi) by pressure / vacuum
tester and leave for 30 seconds.
9. If the reading drops, leakage may occur from oil
seal. Inspect oil seal for damage or wear.
10. Remove plugs from exhaust port and intake
port after this inspection, and reinstall all the re-
moved parts.
6-5 Removing and inspecting cylinder
1. Remove muffl er.
2. Remove four bolts and remove cylinder (A) with
intake insulator (B) and intake bellows (C) from en-
gine.
NOTE:
If it is hard to remove cylinder, gently tap
cylinder head at carburetor side and muffl er side
with a plastic hammer.
3. Inspect cylinder combustion chamber. Clean it
with a wooden scraper if carbon is found.
NOTE:
Never use metal scraper in cylinder com-
bustion chamber to avoid damage.
4. Replace cylinder with new one if plating is worn,
peeled away or scored, exposing cylinder base
metal.
F
G
A
B
C
D
E
A
B
C
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