Servicing Fluid Pump - AIRLESSCO ALLPRO 1200G Service & Operation Manual

PROBLEM
The engine and displace-
ment pump operates, but
paint pressure is too low or
none
The displacement pump
operates, but the output is
too low on the downstroke
or both strokes.
The displacement pump
operates, but the output
is too low on the upstroke.
Clutch does not engage.
Clutch slippage.
Engine stops

SERVICING FLUID PUMP

Note: Check everything in the Troubleshooting Chart before disassembling the sprayer.
FLUID PUMP DISCONNECT
1. Flush out the material you are spraying, if possible.
2. Follow the Pressure Relief Procedure on Page 6. Stop the pump in the middle of down stroke.
3. Remove the suction tube and fl uid hose (if so equipped) from the fl uid pump. On the LO-BOY, detach the hose from
the front of the fl uid pump. (Fig. 20, item 14)
4. Remove 2 retaining rings and slip the sleeve of the coupling down and remove both coupling halfs. This will dis con nect
fl uid pump from the connecting rod. (Fig. 22, Items 10, 11 & 12)
5. Unscrew the two tie rod locknuts.
6. Pull the pump down off the tie rods.
FLUID PUMP REINSTALL (FIG. 22)
1. Loosen the packing nut and extend piston rod to fully up position. Slip sleeve (189-047)
over the piston rod.
2. Make sure that spacer tubes (301-048) are in place.
3. Connect connecting rod with fluid pump by installing coupling halfs (189-046). Slide sleeve over
coupling halfs. Secure with retaining rings (189-048).
4. Secure the fl uid pump housing to the tie rods (100-328) and screw nuts with lock washers on loosely.
5. Tighten the tie rod nuts evenly to 30 ft. lb.
6. Reconnect fl uid hoses and suction tube (if so equipped).
NOTE: After all the rod locknuts are tight, the alignment of both rods should allow easy assembly and dis as sem bly of
the coupling. If thre is any binding, loosen and retighten all the rod locknuts to improve the align ment. Misalignment
causes premature wear of seal and packings.
7. Tighten the packing nut, until there is resistance, then 1 full turn tighter. Approximately 4 threads will show, when
new packings are installed. Fill the wet cup of the packing nut 1/3 full with TSO.
8. Start the pump and operate it slowly (at low engine speed and pressure setting ) to check the piston rod for
binding. Adjust tie rod lock nuts if necessary to eliminate binding.
9. Run at maximum pressure for several minutes, relieve pressure and repeat step 7.
CAUSE
The pressure setting is too low.
The tip or gun fi lter is clogged.
The tip is worn.
The fl uid displacement pump
fi lter is clogged.
There is a large pressure drop
in the fl uid hose.
The lower check valve ball
is not seating properly.
The upper check valve ball is not
seating properly.
The lower packings are worn or
damaged.
SOLUTION
Increase the pressure, see page 4, step 5.
Remove the tip and/or fi lter and clean them.
Replace Tip.
Clean the fi lter.
Use a larger diameter hose.
Service the lower check valve
see page 16
Service the upper check valve per
page 16.
Replace the packings. See page 17.
See Troubleshooting page 19.
Call Authorized Service Center.
Refer to Engine Manual.
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