4. Place spring (422) and ball (421) in handle bracket (426).
5. Depress spring and ball with handle (420) and install pin (425) with washers (424)
and pins (423). Bend pin (423) apart.
6. Install spring (427) and handle assembly on square shaft of valve (441) taking
note of the match marks put on during disassembly. The ends of the spring (427)
must straddle the screw (430) on handle bracket (426). Secure handle assembly
to valve with pins (429) and (428). Install sleeves (432) and capscrews (431) on
housing (438). Attach exhaust cover (442) to housing (438) with capscrews (444)
and lockwashers (443).
7. Check throttle handle moves fully left and right without sticking or binding.
Throttle handle should center, by spring force, automatically when released.
n
Motor
Refer to Dwg. MHP0210.
1. Press bearing (465) onto crankshaft counterbalance. Place the connecting rods
(459) on the bushing (476) and hold them in place with the two connecting rod
rings (474). Install connecting rod rings (474) so the chamfered side is next to
the connecting rod (459).
2. Place the sleeve (475) on the crankshaft (473), then install the connecting rod
(459) assembly on the crankshaft (473).
3. Secure the crankshaft counterbalance to the crankshaft with the taper pin (479)
and tighten capscrew (480).
4. Install rotary bushing (466) and attach the adapter valve (468) and valve cover
(469) to the motor housing (463) with at least two capscrews. This is necessary
to correctly locate bearing (465) when installing the crankshaft in the motor
housing (463), shifting it as necessary so each connecting rod (459) end will
project through a cylinder hole.
5. Align bearing (465) in the bore of the motor housing (463) and tap crankshaft
assembly in place until bearing (465) bottoms on the rotary bushing.
6. Check the fit of each compression and oil ring by placing one ring at a time in
the cylinder, making sure that it is not canted or tilted in relation to the cylinder
wall. With a feeler gauge, measure the ring gap.
7. Make sure that compression rings, oil rings, and pistons are absolutely clean.
Carefully place oil rings (458) and compression rings (454) in their respective
grooves on the pistons (455).
NOTICE
•
Do not interchange the compression and oil rings. The plain compression
ring (454) must be placed nearest the head of the piston (455). The oil ring
(458) (identified by several oil channel grooves) must be placed nearest the
skirt of the piston (455).
8. Compression and oil ring joints (gaps) should be staggered and positioned so
that joints (gaps) do not coincide with wrist pin (457) openings. Refer to
9. Rotate the crankshaft so each connecting rod (459) in succession will project
enough beyond the motor housing (463) to permit inserting the wrist pin (457)
through the piston (455) and connecting rod (459).
10. After each piston (455) is assembled to its connecting rod (459), install a gasket
(460) and cylinder (453).
11. Slide each cylinder (453) over the piston (455), guiding it carefully over the
compression and oil rings. Note that the cylinder has four tapered ears around
the skirt of the piston which serve as ring compressors to aid in installation. The
cylinder should go into place by tapping lightly. If force is required, there maybe
an alignment problem which must be corrected before continuing.
12. Secure cylinders (453) to the motor housing (463) by uniformly tightening
capscrews (451) and lockwashers (452).
13. Remove exhaust cap (469). Install rotary valve (467) in adapter valve (468). Align
the drive pins on the rotary valve (467) with the end of the crank shaft (473). The
three drive pins on the crank shaft end of the rotary valve should fit in the holes
in the crank shaft without appreciable play. If the holes in the crank shaft are
elongated, the crank shaft should be replaced. The drive pins are located so that
the rotary valve will always be returned to the correct position.
14. Replace the exhaust cap (469) and secure in position with capscrews (364) and
lockwashers (96).
Piston Head
Wrist pin opening
Install one compression
ring on either side of oil ring
Ends of compression rings
must be staggered to avoid
alignment with wrist pin
opening and ends of oil ring
Colored ends of oil ring
must butt together,
and must not overlap
Compression Ring Groove
A
B
C
D
E
F
(Dwg. MHP0224)
n
Reduction Gear
NOTICE
•
It is important to maintain a clean work area when reduction assemblies
are reassembled. During reassembly clean each part thoroughly and lightly
coat with appropriate lubricant as described in ‘Recommended Lubricants’
in the “LUBRICATION” section of the Product Information Manual.
Refer to Dwg. MHP2773.
1. Lubricate and install ‘0’ rings (62) on ring gear (72). Assemble ring gear (72), cover
(73) and spacer (71). Check dowel and capscrew holes are aligned.
2. Drive dowels (74) into assembly so they are flush with the cover (73).
3. Position assembled parts vertically with the cover (73) down. Install planet
assembly (67) and gear (69) into ring gear (72).
4. Press bushing (55) into sun gear (66) and install sun gear (66) into planet
assembly (67).
5. Lubricate and install ‘0’ rings (51) on ring gear (63). Install ring gear on spacer
(71) being careful not to damage the ‘0’ ring. Align dowel and capscrew holes.
6. Tap dowels (52) into ring gear (63) and spacer (71). Leave approximately 0.37
inch (9 mm) exposed for engagement with input housing (59).
7. Install planet assembly (58) so planet gear teeth mesh in the ring gear (63) and
with the sun gear (66).
8. Carefully install input housing (59) so it locates on dowels (70). Tilt assembly on
the work bench and install capscrews (75) with Loctite® 242 and torque to 21 ft
lbs (28 Nm).
9. Return assembly to the vertical position. Install bushing (55) and on sun gear
(56) and install sun gear (56) in planet assembly (58).
10. Lubricate and install ‘0’ ring (51) on ring gear (53). Line up dowel and capscrew
holes and install ring gear (53) on input housing (59) being careful not to damage
‘0 ring (51).
11. Install planet assembly (54) so planet gear teeth mesh with ring gear and sun
gear.
12. Lubricate and install ‘0’ ring (51) on ring gear (53).
13. Install oil plugs (61) in input housing (59).
14. Press bearing (49) into bore of gear carrier (47). Install retainer ring (50).
15. Install gear carrier (47) on ring gear (53) being careful not to damage ‘0’ ring (51).
Check capscrew and dowel holes are lined up. Install capscrews (60) with Loctite®
262. Torque capscrews (60) to 33 ft lbs (44.7 Nm).
16. Tap dowels (52) through ring gear (53), input housing (59) and gear carrier (47)
until they are just below the flange surface of the gear carrier (47).
n
Drum
Refer to Dwg. MHP2773.
1. Clean surfaces of the drum (80) and gear carrier (47). Apply Loctite® 515 gasket
sealant to drum mating surface. Lower reduction gear assembly into drum (80)
so capscrew and dowel pin holes are aligned. On 8 inch long drums ensure a
spacer is used between the drum and gear carrier flange.
2. Install capscrews (45) and lockwashers (46) with Loctite® 242 and torque to 61
ft lbs (82 Nm).
3. Install dowel pins (44) so they are flush with gear carrier (47).
4. Install fill/drain plugs (48) in gear carrier (47).
5. Apply a thin coat of Loctite® 609 to the outside of seal (43) and install in gear
carrier (47).
6. Place drum in an upright position.
Form MHD56303 Edition 2
9
