Leakage Testing The Crankcase - Husqvarna 525BX Workshop Manual

Repair instructions

7.26 Leakage testing the crankcase

Remove the cylinder cover, spark plug and guard
over the muffler
Loosen the screws holding the carburettor suf-
ficiently so that the sealing plate no. 502 54 11-02
(A) can be slid down between the carburettor and
insulator.
It may be necessary to carefully pry out the carbu-
rettor sufficiently using a screwdriver.
Place a plate (A) between the cylinder and heat
guard by the muffler.
NOTE!
Press down the sealing plates as far as
possible between the bolts to ensure a
proper seal.
Fit the pressure test nipple (B) 503 84 40-01 in the spark
plug hole.
Connect meter 531 03 06-23 to the nipple and
pump up a pressure of
50 kPa (0.5 kp/cm ) in the crankcase.
2
Max. permitted leakage: 20 kPa
(0.2 kp/cm ) per 30 seconds.
2
Connect meter 531 03 06-23 to the nipple and
lower the pressure in the crankcase to 50 kPa (0.5
kp/cm ).
2
Max. permitted leakage: 20 kPa
(0.2 kp/cm ) per 30 seconds.
2
Any leakage can be difficult to localise if the
crankcase is depressurised.
When leakage has been established with a vacuum,
you can apply a slight overpressure (0.1–0.3 kp/
cm ) and at the same time apply a layer of thin oil
2
to the joints and the sealing ring contact surfaces
on the crankcase to make leak detection easier.
Bubbles clearly mark the position of the leakage.
60
- English
A
B