User manual YS 91ST

[. . . ] If everything is fine, open the throttle and enter forward flight. Take note of the amount of smoke like we did in a hover adjustment. It is correct when you see a noticeable steady smoke trail. [. . . ] As soon as the engine stops running, be sure that a fuel line clamp is used in Tube-B to prevent fuel from flowing into the engine. On the final flight of the day, the fuel line clamp should be used to stop the engine in order to prevent rust and corrosion. FUEL AND GLOW PLUG We have found that the fuel and glow plugs listed below will give the best engine performance. Fuel Powermaster 30% Special Heli Blend Cool Power 30% Special Heli Blend Glow Plug _ YS #2 Enya #3 OS #8 Check Valve Factory Set Do Not Adjust Tube (A) Tube (C) 3 15/16"(10cm) FEATURES The 91ST is the latest in helicopter engine technology from YS. It is a bored and stroked version of our popular YS61ST-2 which has been optimized to provide the ultimate in reliable horsepower for your helicopter. New large bore cylinder design for superior operation. New carburetor design for easier adjustments. Same physical size as 61ST-2 , 80ST making it easy to add more power to your helicopter. 2. Since the engine is sensitive to dirt in the fuel, a fuel filter must be used. Tube(C) should be set exactly at 3 15/16" or (10cm) between the engine and check valve. DO NOT use any other type of check valve. The check valve is designed exclusively for the 91ST. Adjust your throttle linkage and curve using the alignment indentations on the carburetor body located on the throttle arm side of the carb body. PLEASE NOTE that the hover position is at 40% see FIG 2. IMPORTANT!Silicone rubber is used in many parts of the YS engine. Use only glow fuel of methanol for cleaning. [. . . ] Be careful to install the check valve in the correct direction. Since the tank is exposed to high pressures, be sure that all connections are tight to prevent pressures leakage. Hover 40% 91ST Parts List # PART# 1 S5101 2 S5102 3 S5103 4 S5104 5 S5105 6 S5106 7 S5107 8 S7108 9 R6108 10 S5110 11 S5111 12 R6211 13 S7113 14 R6115 15 R6217 16 S5116 17 S5117 18 R6120 19 S5119 20 S5120 21 S5121 22 S5122 23 R6124 24 S4125 25 F1546 26 F1555 27 F1556 28 S5128 29 S8130 30 R6230 31 S5131 32 R6203 33 F1260S 34 S7132 35 S5135 36 S7134 37 S8138A 38 S7136 39 S7140 40 S7139 41 S7143 42 S7144 S5143 S8146 S5105S S5119S S4125S DESCRIPTION Crankcase Cylinder Head Head Gasket Head Screws Cylinder Liner Piston Piston Ring Wrist Pin Wrist Pin Retainer Con Rod Crankshaft Front Bearing Rear Bearing Drive Washer Spacer Propeller Nut Back Plate Back Plate Gasket Back Plate Screw Carburetor Body Carburetor Gasket Throttle Barrel Seal Ring Throttle Barrel Retainer Hover Needle Valve Hover Needle O Ring Hover Needle Seat Hover Needle Seat O Ring Needle Detent High Speed Needle High Speed Needle O Ring Low Speed Needle Low Speed Needle O Ring Throttle Arm Carburetor Screws Carburetor Subplate Regulator Subplate Regulator Assy. Diaphram Regulator gasket Regulator Screws Nipple Check Valve Gasket Set O ring set Piston / Ring / Liner Set Carburetor Assy. [. . . ]