________________________________________________________________________________

Yanmar 3TG72 Engine

General Technical Data

Engine Specifications

Engine Model ............... Yanmar 3TG72
Engine Type ............... 4-cycle inline 3-cylinder liquid-cooled gasoline engine
Number of Cylinders ............... 3
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 2.84 (72.0)
Engine Stroke, in (mm) ............... 2.84 (72.0)
Displacement, cu.in (L) ............... 53.6 (0.879)
Rated Engine Power, hp (kW) ............... 25.6 (19.1) at 3400 rpm
Rated Engine Speed, rpm ............... 3400
Peak Torque ............... 53 Nm (39 lb-ft) at 2400 rpm
Low Idle Speed, rpm ............... 1450
Fast Idle Speed, rpm ............... 3570
Compression Ratio ............... 9.5:1
Firing Order ............... 1-3-2
Flywheel Rotation ............... Counter-clockwise facing flywheel
Valve Arrangement ............... Overhead valve (OHV)
Valves Per Cylinder ............... 2
Cylinder Block Type ............... Cast iron
Cylinder Head Type ............... Aluminum alloy
Lubrication System ............... Full-pressure
Oil Pump Type ............... Trochoid gear
Oil Filter Type ............... Full-flow, replaceable spin-on
Cooling System ............... Liquid-cooled
Water Pump Type ............... Belt-driven, centrifugal
Air Cleaner Type ............... Dry canister dual element
Ignition System ............... Electronic distributor type
Starting System ............... Electric Starter
Electrical System ............... 12V
Alternator Capacity ............... 20 or 35A

Fuel System

Fuel System Type ............... Carbureted electronic fuel shutoff
Carburetor Type ............... Horizontal draft down-draft single barrel
Fuel Pump Type ............... Mechanical diaphragm style or electric low pressure
Fuel Operating Pressure, psi (kPa) ............... 2.2-3.6 (15.1-24.8)
Fuel Type ............... Unleaded gasoline 87 octane minimum
Choke Type ............... Automatic thermostatic or manual cable control
Governor Type ............... Mechanical flyweight
Fuel Filter Type ............... Inline disposable pleated paper canister
Fuel Filter Micron Rating, microns ............... 10
Maximum Fuel Pump Lift, ft (m) ............... 3.3 (1.0)
Fuel Tank Return Line ............... Not required internal bypass system
Fuel Shutoff Valve ............... Solenoid activated 12V DC integrated
Main Jet Size Identification ............... Fixed calibrated orifice #98
Pilot Jet Size Identification ............... Fixed calibrated orifice #42
Float Height Setting, in (mm) ............... 0.47 (12.0)
Float Needle Valve Seat Diameter, in (mm) ............... 0.059 (1.5)
Idle Mixture Configuration ............... Adjustable needle valve limiter cap
Governor Linkage Style ............... Direct rod linkage spring loaded anti-backlash
Fuel System Venting ............... Evaporative internal internal bowl vent
Maximum Fuel Consumption, gal/hr (L/hr) ............... 1.69 (6.4)
Continuous Fuel Consumption, gal/hr (L/hr) ............... 1.18 (4.5)

Dimensions and Weight

Overall Length, in (mm) ............... 17.7 (450)
Overall Width, in (mm) ............... 16.0 (405)
Overall Height, in (mm) ............... 20.2 (515)
Dry Weight, lbs (kg) ............... 166 (75)
Wet Weight, lbs (kg) ............... 179 (81)

Maintenance Data

Service Information

Compression Pressure, Standard, psi (MPa) ............... 170.6 (1.18)
Compression Pressure, Limit, psi (MPa) ............... 127.9 (0.88)
Compression Variance Between Cylinders, psi (MPa) ............... 14.2 (0.10)
Lubricating Oil Pressure, Standard, psi (MPa) ............... 42.6-56.8 (0.29-0.39)
Lubricating Oil Pressure, Minimum, psi (MPa) ............... 11.4 (0.08)
Thermostat Valve Opening Temperature, F (C) ............... 160 (71)
Thermostat Valve Full Open Temperature, F (C) ............... 185 (85)
Radiator Cap Relief Pressure Setting, psi (kPa) ............... 12.8 (88.2)
Spark Plug Type ............... NGK BPR5ES
Spark Plug Gap, in (mm) ............... 0.030 (0.76)
Ignition Timing Angle ............... 20 deg BTDC at 3400 rpm
Fan Belt Tension Deflection, in (mm) ............... 0.39-0.59 (10.0-15.0)
Intake Valve Clearance (Cold), in (mm) ............... 0.008 (0.20)
Exhaust Valve Clearance (Cold), in (mm) ............... 0.008 (0.20)

Engine Oil and Coolant

Engine Oil Type .................. SAE 10W-30, SAE 5W-30
API Service Classifications ......................... SF, SG, SH, or SJ
Engine Oil Capacity with Filter, qt (L) ............... 2.54 (2.4)
Engine Oil Capacity without Filter, qt (L) ............... 2.22 (2.1)
Cooling System Total Capacity, qt (L) ............... 3.17 (3.0)

Service Intervals

Change engine oil ............... Every 100 hours
Replace oil filter ............... Every 200 hours
Replace fuel filter ............... Every 250 hours
Service air filter ............... Every 50 hours
Replace air filter ............... Every 250 hours
Change coolant ............... Every 1000 hours
Valve-lash adjustment ............... Every 500 hours
Check fuel system ............... Every 500 hours
Replace spark plug ............... Every 500 hours
Belt inspection ............... Every 100 hours

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ............... 2.8346-2.8350 (72.000-72.010)
Cylinder Bore Maximum Wear Limit, in (mm) ............... 2.8378 (72.080)
Cylinder Bore Out of Round Maximum, in (mm) ............... 0.0008 (0.020)
Cylinder Block Top Surface Flatness Distortion, in (mm) ............... 0.0020 (0.050)
Cylinder Head Bottom Surface Flatness Distortion, in (mm) ............... 0.0020 (0.050)
Connecting Rod Small End Bushing I.D, in (mm) ............... 0.7878-0.7884 (20.010-20.025)
Connecting Rod Big End Bearing Shell I.D, in (mm) ............... 1.5748-1.5756 (40.000-40.020)
Crankshaft Main Journal Diameter, in (mm) ............... 1.7311-1.7315 (43.970-43.980)
Crankshaft Main Bearing Shell I.D, in (mm) ............... 1.7323-1.7331 (44.000-44.020)
Crankshaft Main Journal Clearance, in (mm) ............... 0.0008-0.0020 (0.020-0.050)
Crankpin Journal Diameter, in (mm) ............... 1.5736-1.5740 (39.970-39.980)
Crankpin Journal Clearance, in (mm) ............... 0.0008-0.0020 (0.020-0.050)
Crankshaft Axial End Play, in (mm) ............... 0.0043-0.0083 (0.110-0.210)
Thrust Washer Thickness, in (mm) ............... 0.0768-0.0787 (1.950-2.000)
Piston Skirt Outer Diameter, in (mm) ............... 2.8327-2.8335 (71.950-71.970)
Piston to Cylinder Bore Clearance, in (mm) ............... 0.0016-0.0024 (0.040-0.060)
Piston Pin Bore Inner Diameter, in (mm) ............... 0.7874-0.7877 (20.000-20.009)
Piston Pin Outer Diameter, in (mm) ............... 0.7871-0.7874 (19.993-20.000)
Piston Pin to Piston Pin Bore Clearance, in (mm) ............... 0.0000-0.0006 (0.000-0.016)
Piston Pin to Small End Bushing Clearance, in (mm) ............... 0.0004-0.0013 (0.010-0.032)
Top Ring Groove Side Clearance, in (mm) ............... 0.0024-0.0039 (0.060-0.100)
Second Ring Groove Side Clearance, in (mm) ............... 0.0020-0.0035 (0.050-0.090)
Oil Ring Groove Side Clearance, in (mm) ............... 0.0008-0.0024 (0.020-0.060)
Top Ring End Gap, in (mm) ............... 0.0059-0.0118 (0.150-0.300)
Second Ring End Gap, in (mm) ............... 0.0059-0.0118 (0.150-0.300)
Oil Ring End Gap, in (mm) ............... 0.0079-0.0157 (0.200-0.400)
Intake Valve Stem Outer Diameter, in (mm) ............... 0.2736-0.2742 (6.950-6.965)
Intake Valve Guide Inner Diameter, in (mm) ............... 0.2756-0.2762 (7.000-7.015)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0014-0.0026 (0.035-0.065)
Exhaust Valve Stem Outer Diameter, in (mm) ............... 0.2732-0.2738 (6.940-6.955)
Exhaust Valve Guide Inner Diameter, in (mm) ............... 0.2756-0.2762 (7.000-7.015)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0018-0.0030 (0.045-0.075)
Valve Face Seating Angle, degrees ............... 45
Valve Seat Contact Width, in (mm) ............... 0.0433-0.0512 (1.10-1.30)
Valve Recess Depth, in (mm) ............... 0.0276-0.0354 (0.70-0.90)
Valve Spring Free Length, in (mm) ............... 1.488 (37.8)
Camshaft Main Journal Diameter, in (mm) ............... 1.5728-1.5736 (39.950-39.970)
Camshaft Bearing Bore Inner Diameter, in (mm) ............... 1.5748-1.5758 (40.000-40.025)
Camshaft Journal Clearance, in (mm) ............... 0.0012-0.0030 (0.030-0.075)
Camshaft Lobe Height (Intake), in (mm) ............... 1.3406-1.3425 (34.050-34.100)
Camshaft Lobe Height (Exhaust), in (mm) ............... 1.3406-1.3425 (34.050-34.100)
Camshaft Axial End Play, in (mm) ............... 0.0020-0.0059 (0.050-0.150)
Rocker Arm Shaft Outer Diameter, in (mm) ............... 0.4717-0.4722 (11.980-11.995)
Rocker Arm Bushing Inner Diameter, in (mm) ............... 0.4724-0.4732 (12.000-12.020)
Rocker Arm Shaft to Bushing Clearance, in (mm) ............... 0.0002-0.0016 (0.005-0.040)

Tightening Torques

Cylinder Head Bolts ............... 40-45 lb-ft (54-61 Nm)
Connecting Rod Cap Bolts ............... 23-27 lb-ft (31-37 Nm)
Main Bearing Cap Bolts ............... 40-45 lb-ft (54-61 Nm)
Flywheel Fastener Bolts ............... 58-65 lb-ft (78-88 Nm)
Flywheel Housing Outer Bolts ............... 17-22 lb-ft (23-30 Nm)
Camshaft Thrust Assembly Bolts ............... 7-9 lb-ft (9.8-12.0 Nm)
Crankshaft Front V-Belt Pulley Nut ............... 65-72 lb-ft (88-98 Nm)
Rocker Arm Shaft Support Bolts ............... 17-22 lb-ft (23-30 Nm)
Cylinder Head Valve Cover Nuts ............... 5-7 lb-ft (6.8-9.5 Nm)
Timing Gear Housing Cover Bolts ............... 17-22 lb-ft (23-30 Nm)
Oil Pump Assembly Screws ............... 6-8 lb-ft (8.1-10.8 Nm)
Oil Pump Cover Plate Screws ............... 5-7 lb-ft (6.8-9.5 Nm)
Oil Pan Bottom Drain Plug ............... 22-29 lb-ft (30-39 Nm)
Oil Pan Perimeter Flange Bolts ............... 7-9 lb-ft (9.8-12.0 Nm)
Spark Plug Base Ignition ............... 15-22 lb-ft (20-30 Nm)
Intake Manifold Flange Bolts ............... 17-22 lb-ft (23-30 Nm)
Exhaust Manifold Flange Nuts ............... 17-22 lb-ft (23-30 Nm)
Water Pump Assembly Mount Bolts ............... 17-22 lb-ft (23-30 Nm)
Thermostat Housing Cover Bolts ............... 17-22 lb-ft (23-30 Nm)
Carburetor Base Flange Mount Nuts ............... 13-16 lb-ft (18-22 Nm)
Fuel Diaphragm Pump Body Bolts ............... 13-16 lb-ft (18-22 Nm)
Starter Motor Flange Mounting Bolts ............... 29-36 lb-ft (39-49 Nm)
Alternator Pivot Adjustment Mounting Bolts ............... 14-19 lb-ft (19-26 Nm)
Alternator Tensioning Adjuster Link Bolt ............... 6-8 lb-ft (8.1-10.8 Nm)
Distributor Base Engine Clamp Lock Bolt ............... 6-8 lb-ft (8.1-10.8 Nm)
Oil Pressure Sensor Indicator Switch ............... 9-13 lb-ft (12-18 Nm)
Coolant Temperature Sensor Indicator Switch ............... 14-19 lb-ft (19-26 Nm)
Governor Control Internal Lever Shaft Nut ............... 5-7 lb-ft (6.8-9.5 Nm)
Breather Valve Cover Plate Secondary Screws ............... 3-4 lb-ft (4.1-5.4 Nm)
Fan Pulley Extension Hub Bolts ............... 6-8 lb-ft (8.1-10.8 Nm)

________________________________________________________________________________________

• Yanmar Engines Specs
  
• Yanmar 3T72HA Specs
  
• Yanmar 3T72SA Specs
  
• Yanmar 3T72SB Specs
  
• Yanmar 3T75HL Specs
  
• Yanmar 3T75U Specs
  
• Yanmar 3TG66UJ Specs
  

________________________________________________________________________________

________________________________________________________________________________________

_______________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________