O.S. .21XZ-M 3.5cc Inboard Marine 13951

This is the O.S. 21XZ-M 3.5cc Inboard Marine Engine.

****** Because of the competition nature of this engine,******

******it is NOT covered by the O.S. 2 Year Warranty.******

Features

• O.S. .21XZ-M 3.5cc Inboard Marine 13951

• Designed expressly for 21 class boat racing

• 21D big bore carburetor allows use of high nitro fuel

• Blue anodized water cooled head

Specifications

• Displacement: .21 cu in (3.5cc)

• Bore: 0.640" (16.27mm)

• Stroke: 0.661" (16.8mm)

• Practical RPM: 4,000 - 45,000

• Power Output: 2.75 hp (33,000RPM)

• Crankshaft Size: 1/4-28

• Carburetor Settings:

•   Needle Valve; 1.5 turns from fully closed

•   Mixture Control Valve: Turn clockwise 10° to lean mixture or counterclockwise to richen mixture, adjust in steps of no more than 45-90°

• Distance between mounting hole centers same side: 0.83" (21mm)

• Distance between mounting hole centers opposite side: 1.4" (37mm)

• Distance/mounting tab to center of exhaust: 1.1" (28.5mm)

• Distance/mounting tab to center of cooling inlet: 2.2" (55.6mm)

• Distance from exhaust center to mounting flange bottom: 1.1" (28.5mm)

• Width not including mounting flanges: 1.2" (31.6mm)

• Width including mounting flanges: 1.8" (45mm)

• Height bottom of crankcase to top of intake:

• Height bottom of mounting flanges to top of intake: 2.6" (66.1mm)

• Length from backplate to end of crankshaft: 3.4" (86.5mm)

• Length from backplate to front bearing: 2.5" (64.5mm)

• Length from crankcase center to front bearing: 1.7" (44mm)

Contents

• O.S. 21XZ-M 3.5cc Marine Engine with 0.2mm Head Gasket, Silicone Exhaust Seal, RP7 Turbo Glow Plug, two Dust Caps and Instructions

Requirements

• Glow Fuel: Boat blend with 10-30% nitromethane content, use 20% for break-in

• Exhaust system depending on boat

• Glow plug igniter