Diaphragm Assy Inspection - Yanmar 3YM30 Service Manual

[NOTICE]
1) When a diaphragm is damaged, pressure control inside the crankcase becomes insufficient, and
troubles occur. When the internal pressure of the crankcase decreases too much due to the
damage of a spring, much blowby gas containing oil is reduced in intake air system, and it may
cause the combustion defect by the early dirt of the intake valve or the urgent rotation of the engine
by the oil burning.
When pressure progresses in the crank case too much due to the wrong operation of the
diaphragm and so on, it is considered that oil leakage from the joint of a oil pan, a oil seal and so on
will occur. When a diaphragm is damaged, blowby is discharged from the breathing hole on the
side of diaphragm cover, and not reduced in the intake manifold. Therefore, be careful of the
diaphragm trouble.
2) At lubricating oil replacement or lube oil supply
The amount of lubricating oil isn't to be beyond the standard upper limit (in the engine horizontality,
the upper limit mark of the dipstick). Since the blowby gas reductor is adopted, be careful that the
amount of oil mist may be inducted in the combustion chamber and the oil hammer sometimes may
occur, when the lubricating oil quantity is beyond the upper limit or an engine is operated beyond
the allowable maximum angle of an engine.
[Reassembly]
Replace the diaphragm with new one, when it is damaged.

7.1.2 Diaphragm assy inspection

Refer to 2.2.6(5) for the inspection procedure.
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7. Intake and exhaust system