Sea-doo GTX Limited iS 255 2009, Shop Manual

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Section 02 ENGINE
Subsection 08 (LUBRICATION SYSTEM)
BLOW-BY VALVE
Blow-by Valve Description
The blow-by valve has two main functions:
– It recirculates oil vapors.
– It protects the engine in the event the water-
craft tip over.
To a accomplish the second function, the blow-by
valve has a tip over protection switch (TOPS).
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1. Valve housing
2. Valve sleeve
3. Valve piston
4. Check ball
5. Valve pin (with magnet)
6. TOPS switch of the blow-by valve
Blow-By Valve Operation
Normal Operation
During its normal operation, the blow-by valve al-
lows crankcase vapors to return in the intake sys-
tem where they are harmlessly burned.
The TOPS switch TOPS state is "OFF", no signal
to the ECM.
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NORMAL OPERATION
Tip Over Protection Function
If the watercraft tips over, gravity causes a valve
piston to close and no engine oil will leak out of
the blow-by valve.
In this event, a pin (with magnet) opens a gap
to the TOPS switch (Hall effect sensor) and the
TOPS changes its state to "ON" and sends a sig-
nal to the ECM.
The ECM will shut down the engine by cutting the
ignition and the fuel injection.
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TIP OVER FUNCTION
By-Pass Function
If, for any reason, the valve piston gets stuck
at normal operation and the crankcase pressure
exceeds 40 kPa (6 PSI), the pressure unseats a
check ball and crankcase vapors can bypass the
valve piston.
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