
Section 05
COOLING SYSTEM
Sub-Section 01
(COMPONENTS)
05-01-6
4, Water Flow Regulator Valve
XP Model
A water flow regulator valve has been developed
for the 787 engine so that it can produce the max-
imum horsepower output and yet maintain the
necessary diameter of the injection fitting at the
tuned pipe head for unobstructed water flow.
The water flow regulator valve is mounted directly
onto the muffler.
1. Water supply hose of regulator valve
2. Regulated water to injection fitting at tuned pipe head
3. Water injected into the muffler
NOTE :
The water injected into the muffler
is not egulated by the valve. A calibrated wa-
ter injection fitting of 3.0 mm (.118 in) inside diam-
eter limits water flow into the muffler.
The water flow regulator valve has a calibrated
spring and a tapered needle which regulate the
injected water in the tuned pipe.
CAUTION : Do not change the calibration
of the spring, otherwise serious engine
damage can occur.
At low speed, water pressure in the supply hose
of the regulator valve is not sufficient to overcome
the spring of the regulator valve ; more water is
being delivered to the injection fitting at the tuned
pipe.
At higher speed, water pressure increases in the
supply hose of the regulator valve and gradually
overcomes the return spring of the regulator
valve. Less water is being delivered to the injec-
tion fitting at the tuned pipe.
Adjustment
The water flow regulator valve has been calibrat-
ed at the factory and should not be modified.
If the maximum engine speed can not be attained
or if the engine has poor performance, the water
flow regulator valve should be considered in the
troubleshooting of the problem.
Mark the location of the red plastic adjustment
screw with paint dots for reference purposes.
Fully tighten screw (clockwise) in valve cap.
1. Turn this screw
2. Valve cap
Turn the screw 3 turns counterclockwise (loosen).
The adjustment is now complete.
NOTE :
The water flow regulator valve
should deliver 0.4 gallon per minute at max-
imum engine speed.
Disassembly
5,6, Spring and Cover
Remove the cover of the valve by releasing the
spring.
WARNING : Firmly hold cover to valve
base. The spring inside the valve is apply-
ing a pressure against the cover.
F01E1FA
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F01E1FC
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