Demco LIL'THUMPER User manual

Page 1
AP20005, Rev 14
01/16
LIL’THUMPER
Piston Pump

Page 2
Thank you for purchasing a Demco Lil’ Thumper pump. We feel you have made a wise choice and
hope you are completely satisfied with your new pump. If you have any questions regarding the applica-
tions of certain solutions or chemicals, contact your chemical supplier and follow chemical manufacturer
recommendations as well as all licensing and use restrictions or regulations.
GENERAL INFORMATION
1. Unless otherwise specified, high-strength (grade5)
(3 radial-line head markings) hex head bolts are
used throughout assembly of this sprayer.
2. Whenever terms “LEFT” and “RIGHT” are used in
this manual it means from a position behind sprayer
and facing forward.
3. When placing a parts order, refer to this manual for
proper part numbers and place order by PART NO.,
DESCRIPTION, and COLOR.
WARNING: TO AVOID PERSONAL INJURY OR PROPERTY DAMAGE, OBSERVE FOL-
LOWING INSTRUCTIONS:
Chemicals are dangerous. Know exactly what you’re going to do and what
is going to happen before attempting to work with these products. Improper
selection or use can injure people, animals, plants and soil.
Always wear protective clothing such as coveralls, goggles and gloves when
working with chemicals or sprayer.
Be sure to dispose of all unused chemicals or solutions in a proper and eco-
logically sound manner.
Table of Contents
General information ................................................................................................................................................. 2
Bolt Torque............................................................................................................................................................... 3
Mounting the Pump and Lubrication Requirements ................................................................................................ 4
Rate Adjustment and Start-up Procedure ............................................................................................................... 5
Suggested Plumbing ............................................................................................................................................... 6
Single and Double Piston Parts Breakdown............................................................................................................ 7
Single and Double Piston Pump Parts List.............................................................................................................. 8
Manual Clutch Parts Breakdown and Parts List ...................................................................................................... 9
Piston Wiper Replacement ...................................................................................................................................... 10 &11
Stackpack Replacement.......................................................................................................................................... 12
Determining Sprocket Ratios For Piston Pumps ..................................................................................................... 13
Routine Maintenance and Maintenance Record ..................................................................................................... 14
Trouble Shooting and Pump Storage....................................................................................................................... 15
Pump and Sprayer Checklist ................................................................................................................................... 16
Return Procedures for Chemical Pumps or Related Items
All pumps or related items must be flushed of any chemical (ref. OSHA Section 0910.1200 (d)(e)(f)(g)(h)
and hazardous chemicals must be labeled before being shipped to or carried into Demco for service or
warranty consideration. Demco reserves the right to request a Material Safety Data Sheet from the Pur-
chaser for any pump or related items Demco deems necessary. Demco reserves the right to “disposition
as scrap”pumps or related items returned which contain unknown substances, or to charge for any and all
costs incurred for chemical testing and proper disposal of components containing unknown substances.
Demco request this in order to protect Demco personnel and the environment from the hazards of hand-
ing unknown substances.
WARRANTY POLICY, OPERATOR MANUALS & REGISTRATION
Go online to www.demco-products.com to review Demco warranty policies, operator manuals and register your Demco product.

Page 3
BOLT TORQUE
TORQUE DATA FOR STANDARD NUTS, BOLTS, AND CAPSCREWS.
Tighten all bolts to torques specified in chart unless otherwise noted. Check tightness of bolts
periodically, using bolt chart as guide. Replace hardware with same grade bolt.
NOTE: Unless otherwise specified, high-strength Grade 5 hex bolts are used throughout as-
sembly of equipment.
Torque figures indicated are valid for non-greased or non-oiled threads and heads unless otherwise
specified. Therefore, do not grease or oil bolts or capscrews unless otherwise specified in this manual.
When using locking elements, increase torque values by 5%.
* GRADE or CLASS value for bolts and capscrews are identified by their head markings.
Torque Specifications
Bolt Torque for Standard bolts *
GRADE 2 GRADE 5 GRADE 8
“A”lb-ft (N.m) lb-ft (N.m) lb-ft (N.m)
1/4”6 (8) 9 (12) 12 (16)
5/16”10 (13) 18 (25) 25 (35)
3/8”20 (27) 30 (40) 45 (60)
7/16”30 (40) 50 (70) 80 (110)
1/2”45 (60) 75 (100) 115 (155)
9/16”70 (95) 115 (155) 165 (220)
5/8”95 (130) 150 (200) 225 (300)
3/4”165 (225) 290 (390) 400 (540)
7/8”170 (230) 420 (570) 650 (880)
1”225 (300) 630 (850) 970 (1310)
CLASS 8.8 CLASS 9.8 CLASS 10.9
“A”lb-ft (N.m) lb-ft (N.m) lb-ft (N.m)
6 9 (13) 10 (14) 13 (17)
7 15 (21) 18 (24) 21 (29)
8 23 (31) 25 (34) 31 (42)
10 45 (61) 50 (68) 61 (83)
12 78 (106) 88 (118) 106 (144)
14 125 (169) 140 (189) 170 (230)
16 194 (263) 216 (293) 263 (357)
18 268 (363) -- -- 364 (493)
20 378 (513) -- -- 515 (689)
22 516 (699) -- -- 702 (952)
24 654 (886) -- -- 890 (1206)
Bolt Torque for Metric bolts *
*5$'( &/$66 &/$66
*5$'( *5$'(
&/$66
   $

Page 4
Before using the pump, check the oil. Remove the two 1/2” nylon filler plugs on PP1 and four 1/2” nylon filler plugs on
PP2 (#1). Fill each drive case through the upper fill hole with a good quality 30 weight oil, non-detergent preferred if needed.
Add oil until the oil level is even with the bottom edge of the lower fill hole (2/3 quart per drive case - approx. 21-1/2 oz.).
A funnel with a hose on the neck (similar to the type used to fill automatic transmissions) will make this operation easier.
Replace and tighten all fill plugs. Check the oil level at the start of each day of use and change oil seasonally.
The stackpack gland areas (located in the front of the necks of the pump) must be filled with a good quality grease. Cover
the small drain hole at the bottom of the front of the pump neck tightly with your finger . Pump grease into the zerk fitting
(#1) at the top of the pump neck until the pressure pushes the grease past your finger. Make sure zerks in both necks are
sufficiently greased on the PP2. This puts grease around all stackpack surfaces and increases the life of the stackpack
considerably. Repeat this procedure every six hours of use thereafter. Keep the holes at the bottom of the necks clear of
dirt and other obstructions so that any fluid leaking past the front stackpack can drain out before it has a chance to enter
the drive case.
Grease these zerks and the zerks in the clutch castings at least once for each day of use.
The Lil’ Thumper pump should be mounted firmly to the implement so the pump is in a horizontal position when operating
(as shown above). The drive sprocket (#1) on the pump and the ground wheel drive sprocket (#2) must be in line to prevent
chain jumping and undue wear. There must be a spring loaded chain idler (#3) installed on the non-driven side of the chain.
The pump should be mounted as low as possible in relation to the tanks to facilitate priming. The chain should be
long enough so when the chain idler is loosened the chain can be slipped off the drive wheel sprocket when traveling to and
from the field. Damage may occur to the pump with chain on at speed of over 10 mph.
MOUNTING THE PISTON PUMP
1
Drain
Hole
STACKPACK
GREASE ZERK
SUGGESTED GROUND
DRIVE MOUNTING
1
3
2
3
1
1
LUBRICATION REQUIREMENTS

Page 5
RATE ADJUSTMENT
START-UP PROCEDURE
Check the oil level as described in the “LUBRICATION”section of this manual. Fill tank 1/2 full of water to get loaded radius.
Open the tank outlet valve and any other valves which would restrict the flow of liquid to, or from, the pump. Remove one
of the plugs from the bottom of the inlet manifolds to see if the fluid is up that far and to remove any air locks. Put the plug
back in when all the air escapes. The pump should prime itself after pulling the implement a few feet with the clutch engaged.
Important: The pump must not run more than 50 feet without fluid in it. If the pump fails to prime after trying the
above procedure, remove the inlet manifold plugs to see if there is fluid to the inlet manifolds. If difficulty persists,
refer to the “TROUBLE SHOOTING”section of this manual.
If pump does not prime, it may be necessary to set the rate adjusting pointer to maximum and remove two spray nozzles (to
prevent a high pressure build-up). Drive forward until the pump primes and begins pumping, replace the two spray nozzles,
reset the pump, and check for any leaks resulting from loose fittings, hoses, etc. After all checks have been made, add
chemical and water to fill the tank.
This PUMP is SHIPPED
WITH OIL.
NOTICE! ! !
3
3
2
1
1
2
Application rate for the Lil’ Thumper is determined by using
the slide chart included with the pump. Complete instructions
are on the back of the slide chart. Pump output is determined
by the drive wheel loaded radius, sprocket ratios, and pump
adjustment disc setting.
TO SET THE PUMP APPLICATION RATE:
NOTE: Adjustment is made when drive chain is connected
to drive wheel.
1. Loosen the two bolts holding the plated cast iron pointer
(#1) to the adjustment disc (#2).
2. Insert one finger of the special adjusting wrench (#3) into
the round hole in the numbered adjustment disc as shown.
Turn the adjustment disc clockwise or counter clockwise
to the desired setting. Pointer bolts need to be moved to
center hole for minimum or maximum settings.
3. Retighten the two bolts holding the pointer to the adjust-
ment disc.
Remember that the slide chart is based on spraying water.
Because of variable factors such as differing solution weights,
wheel slippage, etc.ACTUAL FIELD CALIBRATION SHOULD
BE DONE to insure the desired rate being applied. Refer to
the back of the slide chart for an example of proper tip selec-
tion. NOTE: Remove the drive chain from the ground
drive wheel when traveling to and from the field to prevent
possible loss or damage to the chain.
NOTICE!!!
This PUMP is SHIPPED
WITH OIL
FILL EACH PUMP CAVITY WITH 2/3 QT. SAE-30
NON-DETERGENT OIL or fill until oil comes out
the check plug. On a Double Piston Pump (PP2),
fill both sides of housing (requires 1-1/3 qt.).
Rev 1AP21002
Optimum Operating Pressure 20-40 PSI.

Page 6
SUGGESTED PLUMBING FOR PISTON PUMP
Strainer
The suction and discharge lines must be large enough for the flow required. For high volume the hose to the inlet manifolds
must be no less than 1-1/2” diameter reinforced hose on the PP1 and 2” diameter reinforced hose on the PP2. The suction
line should be as short as possible and free from any bends that might cause an air trap. In-line filters or strainers must be
cleaned frequently and they must be large enough not to restrict flow as this may affect output accuracy.
Do not plumb filters, strainers or manifolds directly to the pump manifolds as the extra weight puts undue stress on
the pump manifolds. These items should be mounted to the implement frame and plumbed to the pump using a suit-
able length of hose. It is also strongly recommended to have a pressure gauge plumbed into the discharge line.
Spray pressure can be approximated by selecting the proper size tips for the speed traveled and volume required (refer to
the slide chart provided with your pump). PRESSURE MUST NOT EXCEED 100 PSI. PUMP SPEED MUST NOT EXCEED
210 RPM. OPTIMUM OPERATING PRESSURE IS 20-40 PSI.
Use of a check valve in each discharge is recommended.
SUCTION AND DISCHARGE LINES
Shut-off
Valve
OUTLET
NOTE: Thread sealant should be applied to all threaded fit-
tings before assembly.
DO NOT install a shut-off valve in the discharge line as it may be
left shut and cause extensive damage to the pump and hoses.
Caution: To prevent personal injury, observe the following precaution.
To Tanks
INLET
NOTE: Mounting angle should
be attached to the 7” x 7”Tool
Bar, in a convenient location
where it will not effect the op-
eration of the planter.
NOTE: Be sure to route hose
so as not to interfere with or be
affected by any folding opera-
tions.
Flange fitting connections may
be used if desired.
08/31/10
PK
SPECIFIEDALL DIMENSIONS
DATE
.XXX = ±.010 BEND AND DRAFT
ARE IN INCHES
DATE
THE DRAWING AND ALL
SINGLE PISTON PUMP
INFORMATION THERE
DEMCO
TOLERANCES
5232
DRAWN BY
ENG APPOV.
DESCRIPTION
DRAWING. NO. REV
SCALE: 1:12 SHEET 1 OF 1
_
ON ARE THE PROPERTY OF
±1°
4010 320TH ST. PO BOX 189
BOYDEN, IOWA 51234
.X = .060 MIN. MACHINE SURFACE 250
.XX = ±.030 BREAK ALL SHARP EDGES
UNLESS OTHERWISE
THIRD ANGLE
PROJECTION
PP1

Page 7
62
35
51
38
28
39
18
5
14
54
19
7
8
9
16
15
4
3
30
13
41
42
56
14
58
21
11
61
46
52
60
20
16
37
59
21
11
6
25
24
50
26
33
32
17
17
46
34 27
27
2 1
12
10
44 45
46
66
62
11
46
52
31
53
40
28
1
29
46
45
44
26
18
24 25
25
26
31
22
22
19
46
44
45
33
62
49
49
48
47
63
43 36
55
23
57
ITEM PART # DESCRIPTION QTY
1 00087 SET SCREW .313NC X .313 SOCKET HEAD
2
2 00914 BOLT, .375 NC X 1.50 HEX HEAD GR.5
2
3 01166 SLIDE COVER
4
4 01167 PISTON SLIDE F/ PISTON PUMP
4
5 01168 PISTOM PUMP UHMW PISTON
2
6 01169 DRIVE HUB ADJUSTMENT SIDE
2
7 01171 ecentric piston pump, large
2
8 01172 ECENTRIC, PISTON PUMP SMALL
2
9 01173 PISTON PUMP CONNECTING ROD
2
10 01176 ADJUSTMENT DISC
1
11 01177 BEARINGS TRUST DRIVE HUB
4
12 01191 ADJUSTMENT POINTER
1
13 01265 PISTON PUMP SHAFT
2
14 01313 WASHER, FLAT, .313
4
15 01317 WRIST PIN
2
16 01318 PUMP SNAP RING
4
17 01320 INTAKE VALVE (BLUE)
4
18 01321 EXHAUST VALVE (RED)
4
19 01390 DRIVE HUB ADJUSTING PIN
4
20 01391 WOODRUFF KEY 1-1/4" X 1-1/8"
2
21 01426 PISTON PUMP GASKET
2
22 01516 O-RING MAIN SHAFT
2
23 01517 OIL SEAL F/PISTON PUMP
1
24 01520 O-RING SMALL CYLINDER
2
25 01521 O-RING LARGE CLAMP
3
26 01522 O-RING CHECK VALVE
8
27 01524 PISTON WIPER
4
28 01528 SNAP RING (.1.172" ID)
3
29 01529 ADJUSTMENT POINTER LOCKING PLATE
1
30 01530 PISTON ROD RETAINING BLOCK
2
31 01534 CYLINDER HOUSING
4
32 01535 LARGE CLAMP HALF
12
33 01536 PISTON PUMP MANIFOLD
4
34 01537 SUPPORT RING PISTON WIPER
2
35 01538 END CAP
2
36 01539 SMALL CLAMP
16
37 01597 .250 NPT PLUG BREATHER NYLON .250 NPT
2
38 01599 DRIVE SHAFT
1
39 01979 1.25" MACHINE BUSHING
2
40 01989 ADJUSTMENT CLAMP DRIVE KEY
1
41 01991 O-RING PISTON ROD GUIDE 2
42 01992
BUSHING
2
43 01993 O-RING 2
44 01996
NUT, .313NC NUT SS 34
45 01997
WASHER, SPRING LOCK .313 34
46 01998
WASHER, FLAT, .313
85
47 02000 NUT .25NC HEX SS 16
48 02001
WASHER, .25 SPRING LOCK 16
49 02002
WASHER, FLAT, .25 55
50 02004
BOLT, .25 NC X 2.25 HEX SS 16
51 02005
BOLT, .313NC X 2.50 HEX HEAD GR.5 12
52 02006
.313NC X 1.00 SS HEX BOLT
22
53 02200 HALF DRIVE CASE
1
54 04632 NUT, .375NC NYLON LOCK
2
55 04642 ZERK, GREASE, .25 UNF SF
3
56 5136 STACK PACK SUBASSEMBLY
2
57 11924 HALF DRIVE CASE (CLUTCH SIDE)
1
58 11926 DRIVE HUBE ADJUSTMENT SLIDE
2
59 11927 CENTER DRIVE CASE
1
60 11929 OIL DRIVE HUB SEAL
1
61 F1200 FTG., PLUG, .50"MPT
4
62 F1400 FTG .250 NPT PLUG
10
07/07/08
DATE
DATE
4010 320TH ST. PO BOX 189
BOYDEN, IOWA 51234
THE DRAWING AND ALL
INFORMATION THERE
ON ARE THE PROPERTY OF
DEMCO
pp2es
DRAWN BY
ENG APPOV.
DESCRIPTION
DWG. NO.
REV
SCALE: 1:8
SHEET 1 OF 1
_
dual piston pump
DKY
UNLESS OTHERWISE
SPECIFIEDALL DIMENSIONS
ARE IN INCHES
THIRD ANGLE
PROJECTION
TOLERANCES
.X = .060 MIN. MACHINE SURFACE 250
.XX = ±.030 BREAK ALL SHARP EDGES
.XXX = ±.010 BEND AND DRAFT ±1°
INLET
OUTLET
INLET
OUTLET
Main Shaft Bearing
Pressed In Case
27
34
27
Cutaway View of Piston Wipers
and Support Ring Showing
Proper Installation.

Page 8
REF. PART QTY.
NO. NO. PP1 PP2 DESCRIPTION
PISTON PUMP PARTS LIST
1. 00087 2 2 5/16”-18UNC x 5/16” Socket Set Screw
2. 00914 2 2 3/8”-16UNC x 1-1/2” Hex Bolt
3. 01166 2 4 Pump Connecting Slide Cover
4. 01167 2 4 Pump Connecting Slide
5. 01168 1 2 UHMW Piston
6. 01169 1 2 Drive Hub, adjustment side
7. 01171 1 2 Large Eccentric
8. 01172 1 2 Small Eccentric
9. 01173 1 2 Connecting Rod
10. 01176 1 1 Adjustment Disc
11. 01177 2 4 Drive Hub Thrust Bearing
12. 01191-95 1 1 Adjustment Pointer
13. 01265 1 2 Piston Rod
14. 01313 2 4 SS Piston Thrust Washer
15. 01317 1 2 Wrist Pin
16. 01318 2 4 Wrist Pin Snap Ring
17. 01320 2 4 Intake Manifold Check Valve (Blue)
18. 01321 2 4 Exhaust Manifold Check Valve (Red)
19. 01390 2 4 Drive Hub Adjusting Pin
20. 01391 1 2 1/4” x 1-1/8” Woodruff Key
21. 01426 1 2 Drive Case Gasket
22. 01516 2 2 Main Shaft O-Ring
23. 01517 1 1 Drive Hub Oil Seal (Adjustment Side)
24. 01520 2 4 Cylinder Housing Small O-Ring
25. 01521 3 6 Cylinder Housing Large O-Ring
26. 01522 4 8 Check Valve O-Ring
27. 01524 2 4 Piston Wiper
28. 01528 2 2 Main Shaft Snap Ring
29. 01529-95 1 1 Adjustment Pointer Locking Plate
30. 01530 1 2 Piston Rod Retaining Block
31. 01534 2 4 Cylinder Housing
32. 01535 6 12 Large Clamp
33. 01536 2 4 Intake/Exhaust Manifold
34. 01537 1 2 Piston Wiper Support Ring
35. 01538 1 2 End Cap
36. 01539 8 16 Small Clamp
37. 01597 1 2 1/4” NPT Nylon Breather Plug
38. 01596 1 - 1-1/4” O.D. Main Shaft for PP1
38. 01599 - 1 1-1/4” O.D. Main Shaft for PP2
39. 01979 2 1 1-1/4” I.D. 18 Ga. Machine Bushing
40. 01989 1 1 1/4” x 1/4” x 1” Key
41. 12489 1 2 Piston Rod Guide Bushing O-Ring
42. 01992 1 2 Piston Rod Guide Bushing
43. 01993 1 2 Rear Stackpack Retainer O-Ring
44. 01996 17 34 5/16”-18UNC Stainless Steel Hex Nut
45. 01997 17 34 5/16” Stainless Steel Lockwasher
46. 01998 34 68 5/16” Stainless Steel Flatwasher
47. 02000 8 16 1/4”-20UNC Stainless Steel Hex Nut
48. 02001 8 16 1/4” Stainless Steel Lockwasher
49. 02002 16 32 1/4” Stainless Steel Flatwasher
50. 02004 8 16 1/4”-20UNC x 2-1/4” SS Hex Head Bolt
51. 02005 6 12 5/16”-18UNC x 3” SS Hex Head Bolt
52. 02006 11 22 5/16”-18UNC x 1” SS Hex Head Bolt
53. 02200 1 1 Half Drive Case
54. 04632 1 2 3/8”-16UNC Stainless Steel Locknut
55. 04642 1 2 Grease Zerk
56. 5136 1 2 Stackpack Sub-Assembly
57. 11924 1 1 Half drive Case (Clutch side)
58. 11926 1 1 Drive Hub, Clutch Side
59. 11927 - 1 Center Drive Case
60. 11929 1 1 Drive Hub Oil Seal (Clutch side)
61. F1200 2 4 1/2” NPT Nylon Plug
62. F1400 5 10 1/4” NPT Nylon Plug
63. 02501 2 2 Main Shaft Bearing (pressed in case)
64. 01582 1 1 Pump Rate Chart
65. 11521-95 1 1 Pump Adjusting Tool
- 11474-30 - 1 Tool Storage Bracket
66. 01174 - 1 Connector Drive Hub
Please order replacement parts by PART NO. and DESCRIPTION.
NOTE: The Intake Manifold Check Valves (blue) have weaker springs than the Exhaust Manifold
Check Valves (red).
65
5224 12 Seal Replacement Kit
24. 01520 2 4 Cylinder Housing Small O-Ring
25. 01521 3 6 Cylinder Housing Large O-Ring
26. 01522 4 8 Check Valve O-Ring
27. 01524 2 4 Piston Wiper
43. 01993 1 2 Rear Stackpack Retainer O-Ring
64
REF. PART QTY.
NO. NO. PP1 PP2 DESCRIPTION

Page 9
12/23/08
DKY
DATE
DATE
4010 320TH ST. PO BOX 189
BOYDEN, IOWA 51234
THE DRAWING AND ALL
INFORMATION THERE
ON ARE THE PROPERTY OF
DEMCO
TOLERANCES
pp2manclutch
DRAWN BY
ENG APPOV.
DESCRIPTION
DRAWING. NO.
REV
SCALE: 1:8
SHEET 1 OF 1
_
DOUBLE PISTON PUMP W/ CLUTCH
.X = .060 MIN. MACHINE SURFACE 250
.XX = ±.030 BREAK ALL SHARP EDGES
.XXX = ±.010 BEND AND DRAFT ±1°
UNLESS OTHERWISE
SPECIFIEDALL DIMENSIONS
ARE IN INCHES
THIRD ANGLE
PROJECTION
MANUAL CLUTCH PARTS
BREAKDOWN
REF. PART QTY.
NO. NO. PP1 PP2 DESCRIPTION
1
1
1
24
26
29
46
40
15
43
33
23
34
35
38 15
16
16
37
37
45
41 1
42
44
18
13 A
10
11
9
9
87
2
16
5
53
2
11
10
4
4
31
Bolt the throw out arm bracket (#40) and arm assembly (preas-
sembled at factory) to the top of the pump using two 3/8” bolts.
The 1-1/2” long bolt should be used to attach the return spring
bracket (#20). Connect the return spring (#21) and remove
any remaining shipping tape from the assembly. Loosen set
screw (#1) in clutch throw out shaft connector (#42). Turn
connector, not the shaft, until holes align for the 5/16” x 1-1/2”
bolt (#44) to pass through connector and Yoke (#14). Lock
connector in place by tightening jam nut (#41). Grease the
zerk in the throw out ratchet casting (#33) before using the
pump and as needed thereafter. An occasional drop of oil to
the other moving parts of the clutch will prevent unnecessary
wear. Check to make sure the clutch completely disengages.
The sprocket casting should turn freely. The handle should
return to engage the next cog in the throw out ratchet casting
when the clutch is tripped.
Important: Make sure the clutch throw out yoke pegs fit
loosely in the groove in the clutch yoke casting when the
clutch is engaged.
Attach the pull rope to the eye in the throw out handle to permit
operation of clutch from the tractor cab. To change the direc-
tion of pull for the clutch handle, simply remove the handle
and install it in the opposite position. Then re-hook the throw
out pawl spring in the other hole in the throw out pawl and
move the spring return bracket to the other side of the handle
assembly and re-hook the return spring. Make sure the pawl
works freely on the side of the throw out arm plate.
ADJUSTMENT INSTRUCTIONS
YOKE
PEG
16
28
25
26
27
25
10
17
15
16
10
11
14
10
11
12
20
21
19
22
36
32
30
NOTE: Clutch Throw out Yoke must be positioned as
shown, with block “A” facing the pump.
45 45
45
1. 00087 5 5 5/16” x 5/16” Cup Point Set Screw
2. 01598-95 2 2 1-1/4” I.D. Lock Collar
3. 01193 1 1 Clutch Spring
4. 01976 2 2 1/8” x 1/2” Roll Pin
5. 01549 2 2 1/4” x 1/4” x 1-5/8” Key
6. 01184 1 1/4-30 1 1 1-1/4” I.D. Clutch Yoke
7. 01183 1 1/4-30 1 1 1-1/4” I.D. Sprocket Casting (18 tooth)
8. 01979 1 1 1-1/4” I.D. 18 Ga. Machine Washer
9. 01498-30 2 2 Pump Side Plate
10. 00061 9 9 3/8”-16UNC Hex Nut
11. 00060 8 8 3/8” Lockwasher
12. 02056 - 2 3/8”-16UNC x 11-1/2” Hex Head Bolt
12. 00613 2 - 3/8”-16UNC x 6” Hex Head Bolt Gr. 5
13. 00173 1 1 1/2”-13UNC Locknut
14. 01576-30 1 1 Clutch Throw Out Yoke
15. 00059 4 4 3/8” Flatwasher
16. 00523 5 5 3/8”-16UNC x 1.25” Hex Head Bolt Gr. 5
17. 00349 1 1 1/2”-13UNC x 6” Hex Head Bolt Gr. 5
18. 01525-30 1 - Piston Pump Top Bracket
18. 01526-30 - 1 Piston Pump Top Bracket
19. 02057 - 2 3/8”-16UNC x 12” Hex Head Bolt
19. 04219 2 - 3/8”-16UNC x 6-1/2” Hex Head Bolt Gr. 5
20. 01527-30 1 1 Throw Out Arm Return Spring Bracket
21. 01547 1 1 Throw Out Arm Return Spring
22. 01211-30 1 1 Throw Out Arm Extension Handle
23. 01982 1 1 3/32” x 1-1/4” Cotter Key
24. 01983 1 1 #10 x 2-1/2” Round Head Stove Bolt
25. 07490 2 2 3/16” Flatwasher
26. 01212-95 2 2 Throw Out Roller
27. 01985 1 1 5/16” x 2” Roll Pin
28. 01986 1 1 #10 Nut
29. 01214-95 1 - Throw Out Shaft
29. 01565-95 - 1 Throw Out Shaft
30. 01548 1 1 Throw Out Pawl Spring
31. 01987 1 1 3/8”-16UNC x 2-1/2”FullThread Hex Head Bolt
32. 01185 1 1 Throw Out Pawl
33. 01186-30 1 1 Throw Out Pawl Ratchet Casting
34. 00062 2 2 1/4”-20UNC Hex Nut
35. 04055 2 2 1/4”-20UNC x 1” Hex Head bolt
36. 01213-30 1 1 Throw Out Arm Plate
37. 02592 2 2 3/8”-16UNC Nylon Insert Locknut
38. 00496 1 1 5/8” Machine Washer
39. 00914 1 1 3/8”-16UNC x 1-1/2” Hex Head Bolt Gr.5
40. 01216-30 1 1 Throw Out Arm Bracket
41. 00489 1 1 5/8”-11UNC Jam Nut
42. 01215-95 1 1 Clutch Throw Out Shaft Yoke Connector
43. 02802 1 1 5/16”-18UNC Nylon Insert Locknut
44. 00372 1 1 5/16”-18UNC x 1-1/2” Hex Bolt Gr. 5
45. 05023 4 4 3/16”Grease Zerk
46. 05587 1 1 1.00”X 14GA Machine Washer
47. 01575-30 1 1 Top Pivot Yoke Link
48. 02528 1 1 Clevis Pin
49. 00009 1 1 1/8” Cotter Pin
47
48
49

Page 10
12/18/08
DKY
DATE
DATE
4010 320TH ST. PO BOX 189
BOYDEN, IOWA 51234
THE DRAWING AND ALL
INFORMATION THERE
ON ARE THE PROPERTY OF
DEMCO
TOLERANCES
PPVALVE
DRAWN BY
ENG APPOV.
DESCRIPTION
DRAWING. NO.
REV
SCALE: 1:5
SHEET 1 OF 1
_
PISTON PUMP
.X = .060 MIN. MACHINE SUFACE 250
.XX = ±.030 BREAK ALL SHARP EDGES
.XXX = ±.010 BEND AND DRAFT ±1°
UNLESS OTHERWISE
SPECIFIEDALL DIMENSIONS
ARE IN INCHES
THIRD ANGLE
PROJECTION
G
N
M
K
LKJ
I
PISTON WIPER REPLACEMENT
F
F
G
H
I
A
B
A
D
DE
E
E
E
CC
B
1. Remove small manifold clamps (A), top and bottom, then
remove the inlet and outlet manifolds (B). This exposes the
valves, inlet valves on bottom (blue) (C), and outlet valves on
top (red) (D). Remove valve o-rings (E) making sure valves
are clear of matter and in proper working condition.
2. Remove center large cylinder housing clamp (F). Separate
cylinder housings (G&H) and remove front housing (H) and
o-ring (I).
3. Remove stainless steel piston nut (J), and thrust washer
(K). Pull out the piston (L), and wipers (M) to examine.
Locate the piston wiper support ring (N) lodged in one of
the cylinder housings (G&H). If deep scratches or grooves
are worn into the surface of the wipers or piston they should
be replaced at this time.
4. To reassemble: Place large o-ring (I) over the flare on
the cylinder housing already assembled to the drive case.
Silicone can be used around the sealing areas for extra
sealing.

Page 11
12/18/08
DKY
DATE
DATE
4010 320TH ST. PO BOX 189
BOYDEN, IOWA 51234
THE DRAWING AND ALL
INFORMATION THERE
ON ARE THE PROPERTY OF
DEMCO
TOLERANCES
PPVALVE
DRAWN BY
ENG APPOV.
DESCRIPTION
DRAWING. NO.
REV
SCALE: 1:5
SHEET 1 OF 1
_
PISTON PUMP
.X = .060 MIN. MACHINE SUFACE 250
.XX = ±.030 BREAK ALL SHARP EDGES
.XXX = ±.010 BEND AND DRAFT ±1°
UNLESS OTHERWISE
SPECIFIEDALL DIMENSIONS
ARE IN INCHES
THIRD ANGLE
PROJECTION
5. Insert the wiper support ring (N) into cylinder housing as-
sembled to the drive case (G). Place wipers (M) on the
piston (L) one from each end, with the flat side inward.
Place inner thrust washer (K) on piston rod and insert the
piston (L) and wipers (M).
7. Replace the red valves (D) and o-rings (E) on the top side,
in an upward direction, and replace outlet manifold (B),
clamps (A) and bolts. Do Not Tighten Clamps.
8. Replace the blue valves (C) and o-rings (E) on bottom
side, in an upward direction, and replace inlet manifold (B),
clamps (A) and bolts. Do Not Tighten Clamps.
9. Tighten large center clamp (AA) first to draw cylinder hous-
ings together, then tighten all remaining large and small
clamps.
PISTON WIPER REPLACEMENT
L
M
K
N
G
Proper direction of installation of piston wipers and support
ring over piston.
6. Insert the thrust washer (K) and 3/8” stainless steel nylon
insert locknut (J) and tighten piston. Place the two cylinder
housings (G&H) together and roll the large o-ring (I) over
the flare and into the groove. Secure with large cylinder
clamp (F) and bolts. Do Not Tighten Clamps.
F
F
H
K
J
G
I
OUTLET
A
B
A
D
E
D
E
E
C
C
E
B
INLET
AA

Page 12
12/18/08
DKY
DATE
DATE
4010 320TH ST. PO BOX 189
BOYDEN, IOWA 51234
THE DRAWING AND ALL
INFORMATION THERE
ON ARE THE PROPERTY OF
DEMCO
TOLERANCES
ppstack1
DRAWN BY
ENG APPOV.
DESCRIPTION
DRAWING. NO.
REV
SCALE: 1:4
SHEET 2 OF 2
_
PISTON PUMP STACK PACK REPLACE
.X = .060 MIN. MACHINE SURFACE 250
.XX = ±.030 BREAK ALL SHARP EDGES
.XXX = ±.010 BEND AND DRAFT ±1°
UNLESS OTHERWISE
SPECIFIEDALL DIMENSIONS
ARE IN INCHES
THIRD ANGLE
PROJECTION
12/18/08
DKY
DATE
DATE
4010 320TH ST. PO BOX 189
BOYDEN, IOWA 51234
THE DRAWING AND ALL
INFORMATION THERE
ON ARE THE PROPERTY OF
DEMCO
TOLERANCES
ppstack1
DRAWN BY
ENG APPOV.
DESCRIPTION
DRAWING. NO.
REV
SCALE: 1:4
SHEET 1 OF 2
_
PISTON PUMP STACK PACK REPLACE
.X = .060 MIN. MACHINE SUFACE 250
.XX = ±.030 BREAK ALL SHARP EDGES
.XXX = ±.010 BEND AND DRAFT ±1°
UNLESS OTHERWISE
SPECIFIEDALL DIMENSIONS
ARE IN INCHES
THIRD ANGLE
PROJECTION
STACKPACK REPLACEMENT
1. Remove large cylinder clamp (A), end cap (B), large
o-ring (C) and small o-ring (D). After this has been done
remove stainless steel piston nut (E) and thrust washer (F).
3. Pull and twist off stackpack retainer assembly (H).
A
A
B
E
FDC
AA
A
A
C
D
G
2. Remove large clamp (A). Proceed by pulling the Piston,Large
O-ring (C), Small O-ring (D), and the cylinder hous-
ing assembly (AA) off of the piston rod (G) at the same
time. If this is not done simultaneously the cylinder
housing assembly will have to be disassembled to properly
install wipers & support ring over the piston. Refer to the
Piston Wiper Replacement section on pages 12 & 13.
4. Oilstackpack andO-ring.Insertstackpackretainer assembly
into pump by sliding it over the piston rod.
5. Place large o-ring over the flare on drive case, then slightly
stretch small o-ring.This will help hold it in the lip of the rear
cylinder housing. Place the first thrust washer on piston
rod, then slide the cylinder housings into position with the
piston still lodged in the piston wipers. Roll the large o-ring
over the flare and into the groove.Secure with large cylinder
clamp (A). Insert and tighten the thrust washer and 3/8”
stainless steel nylon insert locknut.
6. Place large o-ring over the flare on the front cylinder hous-
ing then slightly stretch small o-ring. This will help hold it in
the lip of the cylinder housing. Replace end cap and roll
the large o-ring over the flare and into the groove. Secure
with large cylinder clamp (A).
H

Page 13
DETERMINING SPROCKET RATIOS FOR PISTON PUMPS
It may be difficult in some cases to determine the ratio of the drive for the pump system. The
main determining factor is always the size of the driven sprocket in relation to the drive sprocket.
Always divide the drive (powered) sprocket size by the driven sprocket (see examples below).
LOADED RADIUS CHART
TIRE SIZE LOADED RADIUS
T590L 12.4”
T9.5L 13.6”
T11L 13.5”
T12.5L 15.5”
T13.6 26.5”
T16.9 23.2”
T18.4 25.4”
Loaded Radius = Measurement from surface of the ground
to the center of the hub.
The above chart is to be used as a guideline only. Figures
are based upon a sprayer with 1/2 tank of water. Size of
tank, weight of solution, soil condition etc. may alter these
numbers. Check your Loaded Radius with a tape measure.
THIS IS VERY IMPORTANT.
NOTE: On units with press wheels, the radius of the drive wheel can be considered as the number of teeth of the large sprocket
and the radius of the press wheel can be considered as the number of teeth on the driven sprocket. EXAMPLE: If a planter
has a drive wheel with a radius of 17” and the wheel that presses against it has a radius of 6.5”, we can simply divide the drive
wheel radius (17”) by the press wheel radius (6.5”). This gives a ratio of 2.615 to 1. For every revolution of the ground wheel,
the press wheel turns 2.615. Generally, in this case, a sprocket is mounted on the press wheel. This sprocket would turn 2.615
revolutions for every 1 of the ground wheel, and the ratios can be figured as described in the first paragraph.
50 TOOTH
DRIVE SPROCKET
28 TOOTH
PUMP SPROCKET
TIRE
24 TOOTH
SHAFT DRIVEN SPROCKET
18 TOOTH
PUMP SPROCKET
PISTON
PUMP
1. Determine the size (no. of teeth) of the Drive Wheel
Sprocket and the Driven Sprocket.
2. Divide the number of teeth of the Drive Sprocket by the
number of teeth of the Driven Sprocket to determine the
Sprocket Ratio.
EXAMPLE: 50 tooth drive sprocket divided by 18 tooth
driven sprocket = 2.77 sprocket ratio.
For Jack Shaft Driven Pumps
1. Multiply the number of teeth on all Drive Sprockets together.
2. Multiply the number of teeth on all Driven Sprockets
together.
3. Divide Drive Sprocket total by Driven Sprocket total
which equals the Sprocket Ratio.
EXAMPLE: (see Diagram)
(A) Drive Sprockets 50 x 28=1400
(B) Driven Sprockets 24 x 18=432
(C) 1440/432=3.24

Page 14
MAINTENANCE SCHEDULE 6 HRS DAILY *AS NEEDED 50 HRS ANNUALLY
NUTS, BOLTS, CLAMPS, FITTINGS & HOSES
DRIVE CHAIN ALIGNMENT
CLEAN EXTERNAL SURFACES
CHANGE OIL
GREASE CLUTCH
GREASE STACKPACKS
CHECK OIL LEVEL
REPLACE SEALS, ETC.
LUBRICATE CHAIN
ROUTINE MAINTENANCE
* Refer to specific information listed in maintenance, lubrication and other sections of this manual.
DATE TYPE OF MAINTENANCE DATE TYPE OF MAINTENANCE
•
•
•
•
•
•
••
•
•
MAINTENANCE RECORD
Your Lil’ Thumper is designed to require only occasional
light maintenance. Attention to the following procedures
will significantly prolong the useful life of your pump.
1. Make a habit of carefully checking all nuts, bolts, fit-
tings, plugs, hoses and hose clamps daily to see that they
are secure.
2. Check drive chain alignment. If uneven sprocket wear
occurs, loosen the pump mounting bracket and move pump
and bracket accordingly. Keep the drive chain lubricated
with a good quality chain lubricant.
3. Keep the external surfaces of the pump clean. Dirt
and grease can cling to the pump in a heavy layer and may
cause an unnecessary heat build-up which can shorten
the life of your pump. A high pressure spray washer is
recommended to remove dirt and chemicals from the pump
and clutch assemblies after each use. Cover the vent hole
in the 1/4” breather plugs (located in the top of the drive
cases) so water does not enter the drive cases. Uncover
the breather plugs when washing is done.
4. Change the oil in the drive case of your pump annually.
This is done by removing the 1/2” fill plugs and the 1/4”
drain plugs and draining the oil. When all the oil has drained
out, replace the 1/4” drain plugs and fill the drive cases to
the bottom of the check plug hole with a good quality non-
detergent 30 weight oil as described in the “LUBRICATION”
section of this manual.
5. If chemical or water is found in the oil, the stackpack
glands may be leaking. Refer to the “PARTS BREAKDOWN”
section of this manual to replace these parts or see your
dealer for service assistance.
If replacement parts are required, order by part number
and description to insure prompt shipment.
6. Check the weep hole at the bottom front of the pump neck.
Any solution leaking there means that the front stackpack is
worn and should be replaced. Keep the airway in the drive
case breather plug clean. Remove the plug to clean. This
will keep dirt from falling into the drive case.
•

Page 15
TROUBLE SHOOTING FOR PISTON PUMP
PROBLEM PROBABLE CAUSE SOLUTION
Pump will not prime Valves fouled Clean valves
Piston wipers worn Replace Wipers
Strainer plugged Clean strainer
Sucking air in suction line Repair line
Air lock in suction line Reroute suction line
Worn piston Replace piston
Pump puts out too little Valves fouled Clean valves
Piston wipers worn Replace wipers
Strainer plugged Clean Strainer
Sucking air in suction line Repair line
Air lock in suction line Reroute suction line
Worn piston Replace piston
Broken valve spring Replace valve
Improper rate setting Check calibration
Pump puts out too much Improper setting Check calibration
Chemical leaks through Broken valve spring Replace valve
after pump has stopped Valves fouled Clean valves
Solution leaking from Stackpack glands worn Replace stackpacks
weep hole at bottom Piston rod could be worn Replace rod
front of pump neck
Pump leaks oil Oil seal or O-ring worn Replace seals
Too much oil in drive case Lower oil level
Torn gasket Replace gasket
Short term storage - overnight - in steady or rising tem-
peratures: No special precautions are necessary. DO NOT
DRAIN OR ADMIT AIR!
In FallingTemperatures - Shut off valve between tank and
pump. Remove the inlet and outlet hoses and inlet manifold
plugs. Using a long thin rod, drain the inlet valve by pump-
ing the rod up and down into each of the inlet manifold plug
holes until the chemical mixture in the valve bodies and
cylinder runs out (about two cups of fluid). Note: Catch all
draining chemicals and return to tank. Loosen the pump
from the mounting and tip on end to completely drain the
outlet manifolds. Remount the pump. Replace and tighten
the manifold plugs and check oil level in pump.
PISTON PUMP STORAGE
Seasonal storage - Disassemble pump and clean all
internal parts individually. Replace any worn parts such
as piston, piston wipers, stackpacks, piston rod, etc. After
washing all internal parts with soap and water, coat all
parts with motor oil. Reassemble and fill pump with RV
antifreeze. Make sure the valves are installed correctly with
the BLUE valves in the inlet manifold and the RED valves
in the outlet manifold. Refer to the PARTS BREAKDOWN
section of this manual for proper valve placement. Close
and seal all openings.
NOTE: The main factors in the pump affecting output are
the piston, wipers and the valves. It may be advisable to
keep a spare set of wipers on hand and make sure your
dealer has pistons and valves on hand or readily available.
This is to prevent delays during the season in case the pump
is run dry and premature wear is experienced.

Page 16
EQUIPMENT CHECKLIST:
Downtime caused by field breakdowns is costly and time consuming. Many breakdowns can be
eliminated by periodic equipment maintenance. By spending time reviewing this checklist before
seasonal spraying application time and following proper after-season care, you can save time
and money later.
NOTE: DEMCO does not and will not make any recommendations concerning application of various chemicals or
solutions.These recommendations relate to either amount or procedure of materials applied. If you have any
questions regarding application of certain chemicals or solutions, contact your chemical supplier and follow
chemical manufacturer recommendations.
Check Before Going To The Field :
1. NOZZLES
Check tip for excessive wear by checking for grooves in
or near tip opening. Check nozzle spacing by starting
at center and working outwards. Check boom for proper
height.
2. HOSES
Check all hoses for worn or soft spots. Be sure all hose
clamps are tightened and hoses are not kinked or pinched.
Check for leakage in any lines.
3. TANK
Remove and clean agitator orifices. Check orifices for
excessive wear by checking for grooves in or near orifice
opening. Inspect fitting and grommets to insure they are
in good condition.
4. CONTROLS
Check for leakage, plugging, or wear on all valves, fit-
tings, etc. Clean off any build up of foreign material.
5. PUMP
Check to be sure pump turns freely.
6. FRAME
Be sure all bolts are tightened.
7. REPLACEMENT PARTS
Replace all worn or damaged parts.
After Season Care:
NOTE: It is important to wear proper safety equipment
when cleaning the sprayer. See your chemical or
fertilizer package for this information.
1. After spraying chemicals, run water mixed with cleaners
through tank, pump and all hose hookups. If wettable
powder dries out in the system, it is very difficult to
put back into suspension and can cause malfunction,
damage or injury.
2. When cleaned, tank should have all openings closed
or covered to keep dirt from entering.
3. Pump should be flushed with soluble oil and pump ports
plugged to keep out moisture and air.
4. Disassemble tips and rinse with water or cleaning
solution. (Appropriate for chemical sprayed).
5. Clean tip opening with a wooden toothpick. Never use
wire or hard object that could distort opening.
6. Dispose of all unused chemicals or solutions in a proper
and ecologically sound manner.
6. Water rinse and dry tips before storing.
• Keephands,feet,andlooseclothingawayfromrotatingparts.
• Wearprotectiveclothingrecommendedbyyourchemicaland 
fertilizer manufacturer when working with chemicals.
WARNING: To Prevent Serious Injury Or Death
!