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  5. Owner's Instruction Manual

O.S. Engine 91sII Owner's Instruction Manual

Summary of 91sII

  • Page 1

    It is of vital importance, before attempting to operate your engine, to read the general 'safety instructions and warnings' section on pages 2-4 of this booklet and to strictly adhere to the advice contained therein. Also, please study the entire contents of this instruction manual, so as to familia...

  • Page 2: Warnings

    2 remember that your engine is not a " toy ", but a highly efficient internal-combustion machine whose power is capable of harming you, or others, if it is misused or abused. As owner, you, alone, are responsible for the safe operation of your engine, so act with discretion and care at all times. If...

  • Page 3: Notes

    4 take care that the glow plug clip or battery leads do not come into contact with the propeller. Also check the linkage to the throttle arm. A disconnected linkage could also foul the propeller. After starting the engine, carry out any needle-valve readjustments from a safe position behind the rota...

  • Page 4: Installation

    6 as supplied, the fs-70s Ⅱ, fs-91s Ⅱ and fs-91s Ⅱ -p have their throttle lever on the right hand side and needle-valve control on the left. However, where more convenient for certain installations, these positions may be reversed after rotating the carburettor through 180˚ horizontally. Proceed as ...

  • Page 5: Needle-Valve Extension

    8 〈fs-70sⅡ, fs-91sⅡ〉 needle-valve extension the needle-valve supplied with this engine is designed to accept an extension so that, when the engine is enclosed in a cowling, the needle-valve may be adjusted from the outside. An l-shaped rod, of appropriate length, may be inserted in the needle-valve ...

  • Page 6: Propellers

    10 never disassemble the fuel pump or pressure regulator. Their original performance may not be restored after reassembly. Do not obstruct the small rectangular hole in the side of the regulator cover. Do not allow foreign matter to enter the fuel system. Dirt inside the pump or regulator, no matter...

  • Page 7: Starting

    12 since the fs-70s Ⅱ , fs-91s Ⅱ and fs-91s Ⅱ -p are intended to be started with an electric starter, the addition of a spinner assembly for centering the starter sleeve is desirable. Special propeller locknut sets are available for use with spinners. Propeller & spinner attachment ream the propelle...

  • Page 8: Running-In (Continued)

    14 start and adjust the engine as detailed in the starting instructions. Now open the throttle fully and run the engine for no more than 5 seconds with the needle-valve tuned to produce near maximum r.P.M., then, immediately, slow the engine down again by opening the needle-valve approximately one t...

  • Page 9: Care and Maintenance

    16 note: valve clearances of all o.S. Four-stroke-cycle engines must be checked and reset only when the engine is cold. Procedure is as follows. Remove the cover from the rocker-box on top of the cylinder-head, using the correct size allen hex key. 1. Turn the propeller counter-clockwise until compr...

  • Page 10

    18 do not leave unused fuel in the engine at the conclusion of a day's flying. Accepted practice is to cut off the fuel supply while the engine is still running - at full throttle - then, expel as much fuel residue as possible by turning the engine over for 5-10 seconds with the electric starter. Fi...

  • Page 11

    20 c.M2.6x12 c.M3.5x20 c.M3.5x8 c.M2.6x8 c.M2.6x8 n.+m3x22 (c.M3.5x15 ) 2 3-2 3-1 3 4 4-1 4-2 6-4 6-3 6-2 6 6-1 7 5-4 5-3 5-2 5 8 5-1 11 12 13 14 15 1 9 9-1 9-2 10 17 18 30-1 19 16 25 26 26-2 26-1 26-2 27 31 29 28 24 22 23 22 21 20 30 type of screw c...Cap screw m...Oval fillister-head screw f...Fla...

  • Page 12

    22 c.M2.6x12 c.M3.5x20 c.M3.5x8 c.M2.6x8 c.M2.6x8 n.+m3x22 (c.M3.5x15 ) 2 3-2 3-1 3 4 4-1 4-2 6-4 6-3 6-2 6 6-1 7 5-4 5-3 5-2 5 8 5-1 11 12 13 14 15 1 9 9-1 9-2 10 17 18 30-1 19 16 25 26 26-2 26-1 26-2 27 31 29 28 24 22 23 22 21 20 30 type of screw c...Cap screw m...Oval fillister-head screw f...Fla...

  • Page 13

    24 c.M2.6x12 c.M3.5x20 (c.M3.5x15 ) c.M2.6x8 n.+m3x22 c.M3.5x8 c.M2.6x8 2 3-2 3-1 3 4 4-1 4-2 6-4 6-3 6-2 6 6-1 7 5-4 5-3 5-2 5 8 5-1 11 12 13 14 15 1 9 9-1 9-2 10 17 18 31-1 19 16 25 26 27-2 27-1 27-2 27 31 29 28 24 23 23 22 21 20 30 32 c.M2.6x12 c.M3.5x20 (c.M3.5x15 ) c.M2.6x8 n.+m3x22 c.M3.5x8 c....

  • Page 14

    26 carburettor exploded views & parts list ＊ n.+m3x6 n.+m3x22 s.3x3 1 1-1 1-3 1-2 1-5 1-4 4 8 2 9 3 5 5-1 5-2 6 7 n.+m3x6 n.+m3x22 s.3x3 1 1-1 1-3 1-2 1-5 1-4 4 8 2 9 3 5 5-1 5-2 6 7 needle valve assembly needle assembly "o" ring (2pcs.) set screw needle valve holder assembly ratchet spring carburet...

  • Page 15: Three View Drawing

    28 fs-70sⅡ 11.50cc/0.702cu.In. 25.8mm/1.016in. 22.0mm/0.866in. 2.000〜12.000r.P.M. 1.1bhp/11.000r.P.M. 580g/20.4oz. 58 39.6 20.3 96.4 unf5/16-24 66.3 44.7 55.8 21 50 dimensions(mm) displacement bore stroke practicalr.P.M. Output weight specifications three view drawing ■ ■ ■ ■ ■ ■ c copyright 2000 by...