O. S. Max Engines 91 FX OS Max 91 FX Engine


This is one of the O.S. FX Series of High-Performance Engines. This series of engines is Used in Sport and Aerobatic Aircraft. The FXs are Designed to use a Muffler or Tuned Pipe. 
This Ringed engine has a steel liner.

Radio Control Engine
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Team Associated Replacement Engine

Description 91FX

Construction Ring
Displacement  0.912 (cu in) 
Bore (in) 1.09 
Stroke (in) 0.976 
Output 2.8 at 15,000 (hp @ rpm)
Practical RPM 2,000 - 16,000

Features

One-piece crankcase
Twin ball bearing-supported crankshaft
Schnuerle porting (AKA Schnuerle scavenging)
Aluminum piston, steel cylinder liner and iron piston ring
Side exhaust with muffler with rotatable exhaust outlet
Carburetor with remote needle mounted on the engine back plate (to keep fingers away from the spinning propeller).

O. S. Max Engine 91 FX - O S Max 91 FX Engine

Requirements

Fuel: 18% (minimum) conventional lubricant content and 5%-20% Nitro.

What is included?

One Assembled O. S. Max Engine 91 FX engine with carb
One Expansion style muffler #E-4020 with screws
One O.S. #8 glow plug OSMG2691
One package illustrated instructions, parts list, and O.S. decal

New, Open Box, Never Used.

On Sep-23-17 at 15:31:55 PDT, seller added the following information:

O-S-Max-Engines-91-FX-OS-Max-91-FX-Engine-New

Dimensions 

  • A = 2.05 mm
  • B = 0.98 mm
  • C = 3.9 mm
  • D = 2.4 mm
  • E = 4.06 mm
  • F = 2.62 mm
  • G = 1.69 mm 
  • H = 2.13 
  • J = 3.21

This is one of the O.S. FX Series of High-Performance Engines. This series of
engines is Used in Sport and Aerobatic Aircraft. The FXs are Designed to
Use a Muffler or Tuned Pipe. This Ringed engine has a steel liner.

FEATURES
  • One-piece crankcase
  • Twin ball bearing-supported crankshaft
  • Schnuerle porting (AKA Schnuerle scavenging)
  • Aluminum piston, steel cylinder liner and iron piston ring
  • Side exhaust with muffler with rotatable exhaust outlet
  • Carburetor with remote needle mounted on the engine back plate (to keep fingers away from the spinning propeller).

O. S. Max Engine 91 FX O. S. Max Engine 91 FX

  • Weight w/o Muffler 19.4 (oz)
  • Muffler E-4020
  • Carburetor model 60F
  • Recommended Break-in Prop 16x14
  • Compatiable Propellers 13x6, 13x8, 13x10, 14x6, 14x8, 14x10, 15x6, 15x8, 16x6
  • Glow Plug # 8

SPECIFICATIONS
  • Displacement: 14.95cc (0.912 cu in)
  • RPM range: 2,000 - 16,000
  • Bore: 27.7mm (1.090")
  • Stroke: 24.8mm (0.976")
  • Compression Ratio: 10.1 : 1
  • Weight: 550g (19.42oz) 24.3oz w/muffler
  • Horsepower: 2.8 BHP at 15,000 RPM
  • Length: 96mm the distance from the backplate to drive washer
  • Width: 42.6mm width of engine neglecting engine mounting flanges
  • 52mm distance between centers of the mounting holes
  • Height: 103mm
  • Crankshaft Thread Size: 5/16-24
  • Props: recommend a 13x8 or 13x9 prop (6/99)

NOTE: Exhaust port same size as .61SF so can use 61SF Header w/91 Pipe
High Speed Needle: 1.5 - 2 turns out from fully closed
Low Speed Needle: 2mm gap between the needle and spray bar at full throttle (looking down the neck of the carb)