OS MAX 120AX w/5020 Silencer

The distinctive shape is hard to ignore, and with peak power of 3.1PS at 9000RPM, you can be sure that this engine loves big propellers! OS recognised that engines of this size are often used in scale models and have developed a silencer system that allows adaption to some of the 'tightest' installations. The carburettor features a neat needle valve that protects fingers while adjusting, yet is simple & accessible.

REQUIREMENTS

Fuel: Two-Stroke with 18 lubricant and 5-20 nitromethane
Propeller: 15x10-12 or 16x8-10
Field Equipment: Glow starter, fuel filter, fuel pump, fuel tubing

Displacement: 1.218 cu in (19.96cc)
Bore: 1.197 (30.4mm)
Stroke: 1.083 (27.5mm)
Practical RPM: 1,800 - 9,500 RPM
Power Output: 3.1 PS, 3.06HP9000 RPM
Weight of engine: 29.0oz (823g) with muffler
Weight of muffler: 7.074oz (219.2g) with 90 adapter installed
Weight of muffler: 7.907oz (245g) with extension installed
Crankshaft thread size: 516-24
Distance Between Mounting Holes Same Side: 0.98 (25mm)
Distance Between Mounting Holes Opposite Side: 2.3 (58mm)
Distance Center of Crankcase to End of Crankshaft: 4.3 (109.5mm)
Distance Center of Crankcase to Drive Hub: 2.7 (69.8mm)
Width Between Mounting Tabs: 2.6 (67mm)
Width of Crankcase Below Mounting Tabs: 1.8 (46.5)
Length from Backplate to End of Crankshaft: 5.5 (139.9mm)
Length from Backplate to Drive Hub: 3.9 (100.2mm)
HeightBottom of Crankcase to Top of Cylinder Head: 4.3 (109.2mm)
HeightBottom of Mounting TabsTop of Cylinder Head: 3.4 (85.7mm)
Distance center to center of muffler mounting holes: 48mm (1.89)
Needle Settings: High Speed: 2 - 2.5 turns out from fully closed
Low Speed: 34 turn out from fully closed with the
throttle fully closed