The Kubota Z751 is a 0.75 L (743 cc, 45.34 cu·in) straight-two, water-cooled naturally aspirated vertical diesel engine manufactured by Kubota for general-purpose applications.
A 76.0 mm (2.99 in) cylinder bore and 82.0 mm (3.23 in) piston stroke give the Kubota Z751 engine a total of 743 cc of displacement. The compression ratio rating is 21.0:1.
The Z751 diesel engine produced 17.3 PS (12.7 kW; 17.0 HP) at 2,800 rpm of output power.
The breakdown of the engine code is as follows:
Z – 2-cylinders
751 – Approximate displacement 750 cc
General information
Engine Specifications
Engine code
Z751A
Layout
Straight-2, vertical diesel engine
Fuel type
Diesel fuel No.2-D
Production
–
Displacement
0.75 L, 743 cm3 (45.34 cu in)
Max. Horsepower
17.3 PS (12.7 kW; 17.0 HP) at 2,800 rpm
Torque output
–
Injection type
Indirect injection
Cooling system
Liquid-cooled
Fuel system
Fuel injection pump
Fuel nozzle
–
Starting system
Electric starting with 12V starter
Starting support device
–
Governor
Centrifugal ball mechanical governor
Power adder
None
Firing order
1-2
Dimensions (L x W x H):
–
Weight
–
Cylinder block
Cylinder block
Compression ratio:
21.0:1
Cylinder bore:
76.0 mm (2.99 in)
Piston stroke:
82.0 mm (3.23 in)
Number of piston rings (compression / oil):
2 / 1
Cylinder inner diameter:
76.000-76.020 mm (2.992-2.993 inches)
Piston skirt diameter
–
Piston ring side clearance:
Second
0.090-0.120 mm (0.004-0.005 in)
Oil
0.020-0.050 mm (0.0008-0.0020 in)
Piston ring end gap:
Top
0.300-0.450 mm (0.0118-0.0177 in)
Second
0.300-0.450 mm (0.0118-0.0177 in)
Oil
0.250-0.400 mm (0.0098-0.0157 in)
Piston pin outer diameter
23.002-23.011 mm (0.9056-0.9059 in)
Crankshaft main journal diameter:
51.921-51.940 mm (2.0441-2.0449 in)
Crankpin diameter:
43.959-43.975 mm (1.7307-1.7313 in)
Cylinder head
Cylinder head
Valve Arrangement:
OHV, gear drive
Valves:
4 (2 valves per cylinder)
Valve timing:
INTAKE
–
EXHAUST
–
Valve seat width:
INTAKE
2.100 mm (0.080 inch)
EXHAUST
2.100 mm (0.080 inch)
Valve stem diameter:
INTAKE
7.960-7.975 mm (0.3134-0.3140 in)
EXHAUST
7.960-7.975 mm (0.3134-0.3140 in)
Valve spring free length:
INTAKE
42.0 mm (1.6535 in)
EXHAUST
42.0 mm (1.6535 in)
Cam height:
INTAKE
33.36 mm (1.3134 in)
EXHAUST
33.36 mm (1.3134 in)
Camshaft journal diameter:
39.935-39.950 mm (1.5722-1.5728 in)
Tightening torque
Tightening torque specs
Cylinder head screw:
75.0-78.0 Nm (7.65-7.80 kgf·m, 55.3-58.0 lb·ft)
Connecting rod screw:
37.0-41.0 Nm (3.8-4.2 kgf·m; 27.3-30.3 lb·ft)
Flywheel screw:
54.0-58.0 Nm (5.5-5.9 kgf·m; 39.9-42.8 lb·ft)
Idle gear shaft screws:
32.4-37.3 Nm (3.3-3.8 kgf·m; 23.9-27.5 lb·ft)
Bearing case cap screws:
30.0-34.0 Nm (3.0-3.4 kgf·m; 22.0-25.0 lb·ft)
Maintenance data
Valve clearance
Intake valve
0.18-0.22 mm (0.007-0.009 in)
Exhaust valve
0.18-0.22 mm (0.007-0.009 in)
Oil system
Recommended engine oil
DS or DM
SAE viscosity number
SAE 80
Engine oil capacity
3.8 liters (4.02 US.qts, 3.34 Imp. qts)
Fuel system
Injection timing:
25° B.T.D.C.
Fuel injection pressure
13.73-14.71 MPa (140-150 kgf/cm2, 1991-2133 psi)
Cooling system
Coolant capacity:
5.3 liters (5.6 US.qts, 4.7 Imp. qts)
Electrical system
Battery:
12V, 65Ah or equivalent
Author:Sergei WersAbout: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.
The Kubota Z751 is a 0.75 L (743 cc, 45.34 cu·in) straight-two, water-cooled naturally aspirated vertical diesel engine manufactured by Kubota for general-purpose applications. 
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