Husqvarna 390XP Workshop Manual page 45

17.4 Leakage testing
The following parts must be removed to pressure test
the crankcase and cylinder:
• Carburettor.
• Muffler.
To do a pressure test:
1. Remove the support ring in the intake manifold.
2. Fit cover plate (Refer to pos. 2a "3 Service tools" on
page 8) with M4x15 mm bolt on the intake
manifold. See fig. 13.
3. Fit cover plate (Refer to pos. 2b "3 Service tools" on
page 8) with M6x20 mm on the exhaust port. See
fig. 12.
4. Connect pressure testing tool (Refer to pos. 3 "3
Service tools" on page 8) to the cover plate on
the intake manifold. See fig. 14. The decompression
valve should be closed.
5. Plug the hose to the impulse channel.
6. Pressurize to 80 kPa (0.8 bar).
7. Wait 30 seconds.
8. The pressure must not fall below 60 kPa (0.6 bar).
9. Leakage can occur in the decompression valve and
crankshaft seals.
10. Assemble:
• Carburettor.
• Muffler.
Fig. 12
Fig. 12
Fig. 12
Fig. 12
Fig. 13
Fig. 13
Fig. 13
Fig. 13
Fig. 14
Fig. 14
Fig. 14
Fig. 14
Piston and cylinder
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