Mercury 25 2-stroke engine specs
| Engine Model: Mercury 25 Hp |
| Engine Type: 2-stroke 2-cylinder gasoline outboard engine |
| Total Displacement: 24.4 cu.in (400 cc) |
| Rated Engine Power: 25 Hp (18.7 kW) at 6000 rpm |
| Fuel System: Float type carburetor |
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Engine Model .............. Mercury 25 Hp
Engine Type .............. 2-stroke 2-cylinder gasoline outboard engine
Number of Cylinders .............. Two
Displacement, cu.in (cc) .............. 24.4 (400)
Cylinder Bore, in (mm) .............. 2.56 (65.0)
Piston Stroke, in (mm) .............. 2.36 (60.0)
Maximum Engine Power, hp (kW) .............. 25.0 (18.7)
Maximum Engine Speed, rpm .............. 5000-6000
Low Idle Speed, rpm .............. 750±50
Fast Idle Speed, rpm .............. 1400±250
Firing Order .............. 1-2
Ignition System .............. Capacitor discharge
Starting System .............. Manual Start / Electric Start
Electrical System Rating, Volts .............. 12
Charging System .............. Alternator
Alternator Rating, Amps .............. 4/6
Transom Height (Short Shaft), in (mm) .............. 15 (381)
Transom Height (Long Shaft), in (mm) .............. 20 (505)
Outboard Weight (Short Shaft), lbs (kg) .............. 114 (52.0)
Outboard Weight (Long Shaft), lbs (kg) .............. 117 (53.0)
Fuel System Type .............. Carburetor
Carburetor Type .............. Float
Fuel Pump Type .............. Integral
Fuel Type .............. Automotive unleaded gasoline (octane rating 87 or higher)
Operating Fuel/Oil Ratio .............. 50:1
Fuel Tank Capacity, gal (L) .............. 6.6 (25.0)
Gear Shift .............. Full (forward, neutral, reverse)
Gear Ratio .............. 2.25:1
Number of Teeth (Forward Gear) .............. 27
Number of Teeth (Pinion Gear) .............. 12
Forward Gear Backlash .............. Not Adjustable
Reverse Gear Backlash .............. Not Adjustable
Water Pressure / RPM, psi (bar) .............. 2-7 (0.14-0.48) / 2000
Trim System ................ Manual Trim and Tilt
Trim Position ................ 6
Transom Height (Short Shaft), in (mm) .............. 15 (381)
Transom Height (Long Shaft), in (mm) .............. 20 (505)
Steering System ................ Tiller handle
Diameter, in (mm) ................ 10.4 (263)
Pitch, in (mm) ................ 11 (280), 12 (305), 13 (330)
Number Of Blade ................ 3
Material ................ Aluminum
Cylinder Bore Type .............. Chrome / Mercosil
Cylinder Bore Inside Diameter (Std), in (mm) .............. 2.562 (65.010)
Cylinder Bore Inside Diameter (Max), in (mm) .............. 2.565 (65.090)
Cylinder Bore (Max Out of Round), in (mm) .............. 0.003 (0.08)
Cylinder Bore (Max Taper), in (mm) .............. 0.003 (0.08)
Crankshaft Top Main Bearing Journal, in (mm) .............. 1.251 (31.77)
Crankshaft Center Main Bearing Journal, in (mm) .............. 1.000 (25.40)
Crankshaft Bottom Main Bearing Journal, in (mm) .............. 1.125 (28.58)
Crankshaft End Play (Free), in (mm) .............. 0.004-0.019 (0.10-0.64)
Crankpin End Inside Diameter, in (mm) .............. 1.196 (30.38)
Piston Type .............. Aluminum
Piston Outside Diameter (Std), in (mm) .............. 2.5583-2.5593 (64.98-65.00)
Piston Outside Diameter (Wear Limit), in (mm) .............. 2.5578 (64.967)
Piston Pin End Inside Diameter, in (mm) .............. 1.196 (30.38)
Piston to Cylinder Bore Clearance, in (mm) .............. 0.003-0.004 (0.076-0.101)
Ring End Gap, in (mm) .............. 0.011-0.025 (0.28-0.64)
Engine Fuel Type .............. Automotive unleaded gasoline (octane rating 87 or higher)
Fuel Tank Capacity, gal (L) .............. 6.6 (25.0)
Engine Oil Type .............. NMMA TC-W II or TC-W III 2-cycle outboard oil
Engine Oil Capacity, qts (L) .............. 0.53 (0.50)
Lubricant Type .............. Quicksilver gear lube premium blend
Gearcase Capacity, qts (L) .............. 0.28 (0.26)
Fuel Filter Part Number .............. 35-87946Q04
Spark Plug Type .............. NGK BP8H-N-10
Spark Plug Gap, in (mm) .............. 0.040 (1.01)
Spark Plug Hex, in (mm) .............. 0.71 (18.0)
Maximum BTDC, deg .............. 25±1 at 5500 rpm
Idle Mixture Screw .............. 1-1/4±1/4 turn
Float Level, in (mm) .............. 1.0 (25.4)
Main Jet Size (WMC-45), in (mm) .............. 0.076 (1.93)
Main Jet Size (WMC-53), in (mm) .............. 0.076 (1.93)
Low Idle Speed, rpm .............. 750±50
Wide Open Throttle, rpm .............. 5000-6000
Lubricate all lubrication points .............. Every 100 hours
Inspect and clean spark plugs .............. Every 100 hours
Check fuel line filter .............. Every 100 hours
Check carburetor adjustments .............. Every 100 hours
Check corrosion control anodes .............. Every 100 hours
Drain and replace gear case lubricant .............. Every 100 hours
Lubricate splines on the drive shaft .............. Every 100 hours
Inspect battery condition .............. Every 100 hours
Check control cable adjustments .............. Every 100 hours
Check tightness of bolts, nuts, and other fasteners .............. Every 100 hours
Clean fuel tank pick up filter .............. Every 200 hours
Cylinder Block, Nm (ft-lb) .............. 40.7 (30)
Fuel Pump Cover, Nm (ft-lb) .............. 4.9 (3.6)
Exhaust Manifold, Nm (ft-lb) .............. 15.8 (12)
Flywheel to Crankshaft, Nm (ft-lb) .............. 78 (57.5)
Connecting Rod, Nm (ft-lb) .............. 19.8 (15)
Exhaust Cover, Nm (ft-lb) .............. 21 (15.8)
Crankcase Cover, Nm (ft-lb) .............. 41 (30)
Cylinder Block Cover, Nm (ft-lb) .............. 21 (15.8)
Thumb Assembly, Nm (ft-lb) .............. 15.8 (12)
Troll Bracket Cover, Nm (ft-lb) .............. 44 (32.5)
Steering Link Assembly, Nm (ft-lb) .............. 44 (32.5)
Drive Shaft Housing to Block, Nm (ft-lb) .............. 27 (20.1)
Drive Shaft Housing Washer, Nm (ft-lb) .............. 9.6 (7.2)
Gear Housing Assembly, Nm (ft-lb) .............. 6.8 (5.1)
Pinion Gear, Nm (ft-lb) .............. 20.3 (15)
Propeller Nut, Nm (ft-lb) .............. 22.6 (16.7)
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