O.S. FS-120S-E Surpass 4-Stroke w/o Pump OSMG0930

This is one of the O.S. Surpass series of 4-stroke model engines.

The Surpass series is the 2nd series of 4-stroke engines (The 1st series was

the FS series, discontinued and replaced by the Surpass series around 1986-7).

"Surpass" refers to the fact that this series gained 30% more power than the previous FS series.

Features

• O.S. FS-120S-E Surpass 4-Stroke w/o Pump OSMG0930

• 30% larger Intake Valves than the FS series

• Ringed Piston

• Rear-mounted updraft Carburetor

• Helix Gear-Driven Camshaft

• Ball Bearing-Supported Camshaft and Crankshaft

• Covered under 2-YEAR WARRANTY

Specifications

• Bore: 31mm (1.22")

• Stroke: 27.5mm (1.08")

• Power Output: 1.9 BHP at 11,000 RPM

• Weight-Without Muffler: 30.5oz (864g)

• Weight-With Muffler: 33.3oz (944g)

• Practical RPM Range: 2,000 - 11,000 RPM

• Crankshaft Thread Size: 5/16-24

• Valve Clearance: Between .04mm and .1mm (or between .0015" and .004", measured between the valve tip and rocker arm)

• Length: 104mm (4.09") from backplate to the front of drive washer

• Width: 47mm (1.85") width of engine neglecting the mounting flanges 58mm (2.28") distance between the mounting hole centersHeight: 138.5mm (5.45")

• Suggested Prop(s): 13x11, 13x12, 14x10, 14x11, 15x8, 16x6, 16x7, 17x6

• Construction: Aluminum and Aluminum alloys

Package Contents

• One Assembled FS-120 Surpass w/Carb and No Pump

• One #F Glow Plug

• One Exhaust Header

• One Exhaust Muffler

• One Choke Valve Extension

• One Set of Instructions, Poster, and Decals

• (Wrenches, Choke Valve Extension, and Mounting Template Are No Longer Included per O.S.)

Requirements

• Fuel: 5%-15% nitromethane with 18% lubricant. Synthetic, castor, or a synthetic/castor blend may be used.

• NOTE: Certain four-cycle fuels cannot be used due to low oil content. However, SOME four-cycle fuels such as the Wildcat 4-Cycle 15% (CATP9109) may be used because it has 18% oil content.

• When choosing fuels for this engine, the modeler must be sure to select a fuel with at least a 18% lubricant content.

• Starting and Field Equipment

• Propeller (see SPECS)

Comments

• Some differences between 4-Stroke and 2-Stroke engines.

• 4-strokes are quieter.

• 4-strokes get better fuel economy.

• 2-strokes generate more RPM (11,000-13,000 RPM with prop while 4-strokes rev to around 9,500 RPM)

• 4-strokes generate much more torque and will swing a larger prop.

• 4-strokes have a realistic sound, like a real aircraft engine.