Yamaha MZ300

Yamaha MZ300The Yamaha MZ300 is a 296 cc (18.0 cu-in) single-cylinder air-cooled 4-stroke internal combustion general-purpose gasoline engine with horizontal shaft manufactured by Yamaha Motor Co., Ltd.

The Yamaha MZ300 engine has an OHV (overhead valve) design; float type carburetor; centrifugal flyweight governor; mechanical splashing lubrication system; Transistor Controlled Ignition (T.C.I.) and recoil or electrical (option) starter. The Yamaha MZ300 used aluminum cylinder block with a spiny cast-iron sleeve. For exhaust valve used high heat resistant SUH3 steel.

The cylinder bore is 80.0 mm (3.15 in) and the piston stroke is 59.0 mm (2.32 in), compression ratio rating is 8.4:1. The engine produced 9.5 PS (7.0 kW) at 3,600 rpm of maximum horsepower and 7.9 PS (5.8 kW) at 3,600 rpm of continuous rated power. Maximum torque is 20.3 N·m (2.07 kg·m, 14.97 ft·lb) at 2,400 rpm of torque.

General information

Engine Specifications
ModelMZ300
Type4-stroke, Hemi-head OHV, single cylinder
Displacement296 cm 3 (18.0 cu-in)
Max. horsepower9.5 PS (7.0 kW) at 3,600 rpm
Max. torque (crank PTO)20.3 N·m (2.07 kg·m, 14.97 ft·lb) at 2,400 rpm
CarburetorFloat type
Cooling systemForced-air
Ignition systemTransistor Controlled Ignition (T.C.I.)
Lubricating systemMechanical splashing
Starting systemRecoil or Electrical (option)
Fuel usedUnleaded gasoline (octane number 86 or higher)
Fuel tank capacity5.5 L (1.45 US Gal, 1.21 Imp Gal.)
PTO shaft rotationCounterclockwise (from PTO shaft side)

Dimensions and Weight

Yamaha MZ300
Length, mm (in)362 (16.2)
Width, mm (in)426 (16.7)
Height, mm (in)426 (16.8)
Dry weight, kg (lb)26.0(57.3)

Service Information

Valve clearance
Intake valve clearance0.10 mm (0.004 in)
Exhaust valve clearance0.10 mm (0.004 in)
Oil system
Oil typeYamalube 4-stroke or an equivalent (SE or SF)
Recommended oilSAE 10W-30, 10W-40
Oil capacity1.0 L (1.06 US. qt, 0.88 Imp. qt.)
Ignition system
Spark plugNGK: BPR4ES
Spark plug gap0.7-0.8 mm (0.028-0.031 in)
T.C.I. air gap0.4 ± 0.2 (0.016 ± 0.008)
Spark plug tightening torque20 N·m (2.0 kg·m, 14 ft·lb)
Author: Sergei Wers
About: 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.

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We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.

1 Comment

  1. I have a question I’m hoping you can answer. Is it possible to put a mz300 generator engine onto a ys624 snowblower? Is there a difference in the crankshaft ends? I know it i has more h.p. but is it the only difference? Thanks

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