Yanmar 4LHA-HTP User Manual

Chapter 7 Reduction and Reversing Gear
3. Inspection and Servicing
4LHA Seriei
3. Inspection and Servicing
3-1 Clutch case and cover
(1) Check the clutch case and cover for cracking with a
test hammer.
Perform a color check when required.
If the case and cover are cracked, replace those together.
(2) Check for staining on the inside surface of the bearing
section.
Also, measure the inside diameter of the case and cover.
Replace the case and cover if these are worn beyond
the wear limit.
3-2 Bearing
(1) Rusting and damage.
If the bearing is rusted or the taper roller retainer is
damaged, replace the bearing.
(2) Make sure that the bearings rotate smoothly.
If rotation is not smooth, if there is any binding, or if any
abnormal sound is evident, replace the bearing.
3-3 Gear
Check the surface, tooth face conditions and backlash of
each gear. Replace any defective part.
(1 )Tooth surface wear.
Check the tooth surface for pitting, abnormal wear,
dents,-and cracks. iRepair the lightly damaged gears
and replace heavily damaged gears.
(2) Tooth surface contact.
Check the tooth surface contact. The amount of tooth
surface contact between the tooth crest and tooth flank
must be at least 70% of the tooth width.
(3) Backlash.
Measure the backlash of each gear, and replace the gear
when it is worn beyond the wear limit.
Clutch shaft
Input shaft
Intermediate shaft
Pick-up gauge
Magnetic stand
mm (in.)
Maintenance
Standard
Wear limit
Input shaft gear
Clutch gear
Idle gear
0.08-0.16
(0.0031 -0.0063)
0.3
(0.0118)
Drive gear
Output shaft gear
0.12-0.20
(0.0047 - 0.0079)
0.3
(0.0118)
3-4 Clutch gear (A) and (B)
(1 (Contact surface with drive cone.
Visually inspect the tapered surface of the clutch gears
(A) and (B) where they make contact with the drive
cone to check if there is any abnormal condition or
sign of overheating.
If any defect is found,
replace the gear.
Tapered surface
3-5 Drive cone
(1)Visually inspect that part of the surface that comes into
contact with the circumferential triangular slot to check
for signs of scoring, overheating or wear. If deep scoring
or signs of overheating are found, replace the cone.
contact surface
Helical involute spline
(2)Check the helical involute spline for any abnormal con-
dition on the tooth surface, and repair or replace the
part should any defect be found.
7-1-10

Yanmar 4LHA-HTP Specifications

General

Brand	Yanmar
Model	4LHA-HTP
Category	Engine
Language	English