Yanmar YM2000 Service Manual

I) Free descent of the implement is continuously
too fast when the engine is shut off, and the
neutral position of the implement is unstable
{sobbing phenomena) during operation.
I I
Spool
l tern
Stop valve
Return spring
Slow return
valve
I
1. Faulty seats
2. Worn out
I
Replace spool & control valve body
Cause
Broken O-ring
Too weak
Broken O-ring
Remedy
Replace
Replace
Replace
2) Implement does not descend.
Piston head
3) Implement cannot be lifted, or lifting is too slow.
1. Broken O-ring
2. Back up ring
Replace
Replace
Remedy
Replace
Replace
Clean or
replace spool & control valve body
Replace
Open
the valve
Replace
l tern
Stop valve
Piston
Spool
Return spring
Slow return valve
Piston
head
Cause
Faulty seat
Does not move smoothly
Foreign matter lodged between the spool and
body
Broken
Valve
is stuck "closed"
Piston stuck
to cylinder
Remedy
Exchange the oil seal
Replace
Replace
Replace
Replace
Replace
Specific pressure
155 kglsq, cm
Replace
Replace
Clean
Supplement
- Replace
Item
Hydraulic pump
Stop valve
Return spring
Crank arm
Relief valve seat
Relief valve
Piston head
Others
Cause
1. Air is sucked in through the oil seal of the pump
shaft
2. Worn gears
3. Insufficient movement
Faulty O-ring
Too weak
Broken
1. Broken-O-ring
2. Back up ring
Pressure is
too low
1. Broken O-ring
2. Back up ring
1. Strainer is clogged
2. Insufficient hydraulic fluid
3. Viscosity of fluid is too high

Yanmar YM2000 Specifications

General

Engine Type	Diesel
Horsepower	20 HP
Type	Compact Utility Tractor
Cooling	Liquid-cooled
Drive	2WD
Hydraulic System	Open center
PTO Speed	540 RPM
Transmission Gears	6 forward, 2 reverse
PTO Power	18 hp
Weight	1, 300 kg