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Yamaha 30DMH 2-stroke engine specs

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• Yamaha 30DMH Engine Specifications
• Yamaha 30DMH Engine Troubleshooting

Engine Model ................ Yamaha 30DMH
Engine Type ................ 2-stroke three-cylinder gasoline outboard engine
Number of Cylinders ................ 3
Displacement, cu.in (cc) ................ 30.3 (496)
Cylinder Bore, in (mm) ................ 2.34 (59.5)
Piston Stroke, in (mm) ................ 2.34 (59.5)
Maximum Engine Power, hp (kW) ................ 30.0 (22.1)
Maximum Engine Speed, rpm ................ 4500-5500
Idle Speed, rpm ................ 700-800
Compression Ratio ................ 6.8:1
Lubrication System ................ Engine oil and gasoline mixture
Exhaust System ................ Through hub exhaust
Cooling System ................ Water cooling with thermostat
Ignition System ................ Capacitor discharge ignition (CDI)
Starting System ................ Manual

Overall Length, in (mm) ................ 39.1 (995)
Overall Width, in (mm) ................ 14.2 (360)
Overall Height (Short Shaft), in (mm) ................ 45.6 (1160)
Overall Height (Long Shaft), in (mm) ................ 50.4 (1280)
Transom Height (Short Shaft), in (mm) ................ 16.7 (425)
Transom Height (Long Shaft), in (mm) ................ 21.5 (545)
Outboard Weight (Short Shaft), lbs (kg) ................ 130 (59.0)
Outboard Weight (Long Shaft), lbs (kg) ................ 134 (61.0)

Fuel System Type ................ Carburetor
Fuel Type ................ Unleaded gasoline (86 octane minimum)
Fuel Consumption, L/hr ................ 13.0
Fuel Tank Capacity, gal (L) ................ 6.4 (24.0)

Gear Shift ................ F-N-R
Gear Type ................ Sriral bevel gear
Gear Ratio ................ 1.85:1
Gear Oil Capacity, qts (L) ................ 0.21 (0.20)

Trim System ................ Manual Trim and Tilt
Transom Height (Short Shaft), in (mm) ................ 16.7 (425)
Transom Height (Long Shaft), in (mm) ................ 21.5 (545)
Steering System ................ Tiller handle
Steering Angle, deg ................ 80
Tilt Angle (Max), deg ................ 70

Diameter, in (mm) ................ 9.12 (231)
Pitch, in (mm) ................ 13 (330)
Number Of Blade ................ 3
Material ................ Stainless steel

Cylinder Bore Inside Diameter, in (mm) ................ 2.3425-2.3433 (59.500-59.520)
Cylinder Bore (Max Out of Round), in (mm) ................ 0.002 (0.050)
Piston Skirt Diameter, in (mm) ................ 2.3407-2.3417 (59.455-59.480)
Piston to Cylinder Clearance, in (mm) ................ 0.0016-0.0018 (0.040-0.045)
Piston Pin Outside Diameter, in (mm) ................ 0.6285-0.6287 (15.965-15.970)
Piston Pin Bore Inside Diameter, in (mm) ................ 0.6289-0.6293 (15.974-15.985)
Connecting Rod Inside Diameter (Small End), in (mm) ................ 0.7876-0.7878 (20.004-20.007)
Top Ring Width, in (mm) ................ 0.0772-0.0780 (1.96-1.98)
Second Ring Width, in (mm) ................ 0.0772-0.0780 (1.96-1.98)
Top Ring End Gap, in (mm) ................ 0.006-0.012 (0.15-0.30)
Second Ring End Gap, in (mm) ................ 0.006-0.012 (0.15-0.30)
Top Ring Side Clearance, in (mm) ................ 0.002-0.004 (0.05-0.09)
Second Ring Side Clearance, in (mm) ................ 0.002-0.004 (0.05-0.09)

Engine Fuel Type ................ Unleaded gasoline (86 octane minimum)
Engine Oil Type ................ Yamalube 2-stroke outboard motor oil or TC-W3 certified outboard oil
Gear Lubricant Type ................ Hypoid Gear Oil or API GL5, SAE 90
Gearcase Capacity, qts (L) ................ 0.21 (0.20)
Ignition Timing, degrees ................ 25 BTDC
Spark Plug Type ................ NGK B7HS-10 or BR7HS-10
Spark Plug Gap, in (mm) ................ 0.035-0.039 (0.9-1.0)

Check Starter Rope ................ Every 50 hours
Check Gear Oil ................ Every 50 hours
Check Fuel Lines ................ Every 100 hours
Check Anodes ................ Every 100 hours
Check Propeller ................ Every 100 hours
Check Spark Plug ................ Every 100 hours
Clean Fuel Tank ................ Every 100 hours
Check Cooling System ................ Every 100 hours
Check Water Pump ................ Every 100 hours
Check Carburetor ................ Every 100 hours
Ajust Ignition Timing ................ Every 100 hours
Check Idling Speed ................ Every 100 hours
Change Gear Oil ................ Every 100 hours
Check Oil Injection Pump ................ Every 100 hours
Replace Spark Plug ................ Every 200 hours
Check Fuel Filter ................ Every 200 hours

Cylinder head bolt, Nm (lb-ft) ................ 28 (21.0)
Flywheel nut, Nm (lb-ft) ................ 110 (80.0)
Crankcase bolt, Nm (lb-ft) ................ 28 (21.0)
Propeller nut, Nm (lb-ft) ................ 35 (25.5)
Clamp lever, Nm (lb-ft) ................ 11 (8.0)
Reed valve, Nm (lb-ft) ................ 4 (2.9)
Exhaust cover, Nm (lb-ft) ................ 8 (5.8)
Spark plug, Nm (lb-ft) ................ 20 (14.0)

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Gasoline and Diesel Engines Technical Data