User manual YS FZ91

[. . . ] Synthetic or castor oil can be used, or a combination of synthetic and caster. The needle valve should be set so that the engine is running at a rich setting. It is advisable to always use a slightly rich setting to keep the moving parts lubricated, even after the break-in period. 52 TAPPETCLEARANCE ADJUSTMENT 1. [. . . ] Gasoline and other volatile solutions will damage the silicone if used. FEATURES The FZ91 is the most powerful 91 four cycle engine available. This engine offers many exclusive features that have been proven on other YS engines. Supercharged system with simplified structure to keep weight to a minimum while still retaining maximum efficiency. Air chamber that uses crankcase pressure coupled with a double throttle valve system which allows a bigger charge of fuel and air mixture to enter the intake valve for more power. Same proven piston design as the 140Limited which creates more crankcase pressure for a more consistent fuel flow to the regulator. This system is unaffected by tank position or by the attitude of the model. PROPELLER INSTALLATION Due to the high torque of the FZ91 engine, we have equipped it with double locknuts for safety. Select a good quality propeller that will turn in the 8, 000 to 11, 000rpm range. We recommend sizes 13~12-14, 13. 5~10-14, 14~10-14. LOW SPEED ADJUSTMENT This engine is equipped with a new low speed needle valve to adjust the mixture from low to mid throttle. This needle valve is located on the side of the throttle barrel opposite the throttle arm(fig. 1). The low speed needle valve should be set after the high speed needle valve has been adjusted. Let it idle for 20 to 30 seconds and then slowly advance the throttle. The adjustment is satisfactory at low speed if transition is smooth at this time. If the engine is running rough on idle, the low speed mixture is rich. If the engine starts to speed up and dies on idle or starts to detonate, when advancing the throttle, the mixture is lean. Turn the low speed needle valve clockwise to richen and counterclockwise for a leaner mixture(note that the direction of the low speed needle valve is opposite the high speed needle valve). Adjustments to the low speed needle valve should be 1/8 to 1/4 of a turn increment at a time to achieve smooth throttle response. If for some reason you have to disassemble the regulator assembly, the regulator adjusting screw should be set flush with the regulator body. FIG. 2 WARRANTY Strict quality control is implemented by our factory in all phases, from parts manufacturing to final assembly. If performance deteriorates or a part fails due to a manufacturing error, YS will repair or replace the engine at no charge. [. . . ] Since high pressure is applied to the tank, tighten all connections carefully. Care must be taken to prevent pressure leakage due to undertightening of the check valve or by kinking the fuel lines. Match the direction of the check valve arrow to fig. 1, with the arrow facing towards the tank. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 F9201 F9202A F9202 F9103 F9104 F1209 F9106 F9107 F9208 R6115 F9210 F9111 F9112 F9113 F9114 F9115 F9116 F9117 F9118 F9319 F9120 F1240 F9122 F9323 F9324 F1266 F1267 F9127 F9128 F9129 F1323 F9131 F1213 F1214 F9134 F9135 F1217 F1235 F9138 F1233 F9140 F1242 F1236 F9143 F9144 F1239 F9146 F9147A F9147 F9148 F9149 F1229 F9151 F9152 F9153 F9354A F9354 F9355 F9156 F9157 F9358 R6124 F1260S F1258 F1259 F1554S F1554 F1546 F1555 F1256 F1557 F9164 F9165 F9166A F9166 F1245 F1246 F9169 F1248 F1249 F1251 Crankcase Cylinder Head Cylinder Head Intake Valve Exhaust Valve Valve Spring Set Spring Retainer Set Valve Spring Retainers Clips Cylinder Head Gasket Draive Washer Spacer Cylinder Liner Head Screws Valve Cover Valve Cover Gasket Valve Cover Screws Air Chamber Air Chamber Gasket Air Chamber Screws Air Chamber O Ring Crankshaft Rear Bearing Front Bearing Front Bearing Oil Seal Drive Washer Drive Washer Retainer Propeller Washer Propeller Nut Set Piston Piston Ring Wrist Pin Wrist Pin Retainer Rocker Arm Set Tappet Adjusting Screw Set Tappet Lock Nut Rocker Arm Shaft Rocker Arm Screw E Ring Set Cam Gear Cam Gear Cover Cam Gear Cover O Ring Cam Gear Cover Screws Cam Gear Bearng Cam Follower Push Rod Push Rod Covers Push Rod Covers O rings Con Rod Rear Cover Assy. [. . . ]