Pump Pressure Setting Procedure - Yamaha PW3028A Service Manual

PUMP PRESSURE SETTING PROCEDURE

PRESSURE SETTING PROCEDURE
See Figures 26-28.
 Attach a (A) high pressure gage that has a (B)
male and (C) female 3/8 quick disconnect on
it to the outlet of the pump. The gage must be
rated to over 5000 PSI and have a discrimination
of not more than 100 PSI. See Figure 26.
 Install a (A) red zero degree nozzle to the (C)
wand extension. The zero degree nozzle is
normally the least used and therefore should
have less wear. If the zero degree nozzle is
missing, any of the other high pressure nozzles
may be used but the outlet pressure may be a
slightly lower due to normal wear of the nozzle.
See Figure 27.
 Assure the RPM of the engine is within specs
of the chart below. Adjust throttle screw
accordingly.
 Squeeze the trigger (have the nozzle (A) pointed
into a plastic drum (B) or equivalent for safety!)
and hold for 15 seconds. Release. Record the
"Bypass Pressure" on the high pressure gage.
See Figure 28.
 If the bypass pressure is lower than the model
listed in the spec charts below, loosen locking
nut on the unloader adjustment while holding
the unloader nut in place (see Fig 29). If the
pressure is over the aoutn specified in the spec
chart, adjust the unloader lower by turning it
counter clockwise.
 Using the spec chart below to check bypass
pressure by squeezing and releasing trigger.
While holding trigger, the output pressure
should meet specs. If unit has a lot of wear or
nozzle is extremely worn, the outlet pressure
will be lower. If pressure is lower than specs,
replace nozzle.
NO LOAD
OUTLET
LOADED
BYPASS
GPM
IDLE DOWN
2200-2800 RPM
2550 PSI Minimum
3350-3500 RPM
4400 PSI Max
2.7 GPM Minimum
2200-2800 RPM
C
C
25
BAR
100xkPa
psi
A
A
B
Fig. 26
Fig. 27
B
A
Fig. 28