User manual YS DZ170

[. . . ] 4 Close the throttle to the idle position and connect the glow driver. DO NOT ATTEMPT TO START ENGINE AT FULL THROTTLE AS THIS IS VERY DANGEROUS. ALWAYS USE EXTREME CAUTION WHEN ENGINE IS RUNNING. If the engine is running rough at idle or too rich, turn the regulator adjustment counter-clockwise to lean out the low end. [. . . ] Next, tighten the frontnutasshowninfig. 2. Therearnuthasanoffsetshoulder so the front nut will secure itself to the rear nut. 2 Select a good quality propeller that will allow the engine to run at maximum speed between 7, 800 to 8, 800 rpm range. Other prop sizes may be used as long as the correct rpm range. CAM GEAR TIMING FEATURES The DZ170 was developed for serious aerobatics competition and large IMAC style aircraft. It differs from previous YS Engines in that it does not use a high pressure fuel system but rather a true fuel pump. *Crankcase supercharging system unique to YS 4 stroke egines *Fuel injected *Convenient fuel pump adjustment *High horsepower output with long service life HIGH SPEED NEEDLE ADJUSTMENT Adjustment of the high speed is done by the carburetor needle valve. When the needle valve is turned clockwise, the mixture is leaner. A good starting position for the high speed needle valve is 2 turns open from the fully closed position. At this setting the engine will be very rich and may die when you remove the glow driver. The final running setting for the high speed needle will be approx- imately 1 to 1-1/2 turns open from fully closed. 2 Whentheengineisstarted, openthethrottlegradually. Next, find thepeakposition(highestRPM)byadjustingtheneedlevalve. Then the needle valve should be opened approximately 1/8 _ 1/4 turns from full RPM to achieve best performance. 1 If for some reason you have to disassemble your engine, please follow these important steps on reassembling the cam gear. Notice the impression mark or dot opposite the rod journal on the crankshaft. This mark is to point straight down or lined up with the outer case seam line at the bottom. 2 Reinstall the cam with the dot facing you and pointing slightly to the left. This will allow the cam to turn to the right when prop erly installed. Reinstall cam cover and timing is now set. GLOW PLUG Select the most appropriate glow plug from those designed specifically for 4 cycle engines. Glow plug selection greatly affects the maximum engine output and low idle. [. . . ] If this type of tank is used, you must use the special clunk supplied with the engine. Please note that with this clunk, all of the fuel cannot be used from the tank. As soon as any part of the clunk becomes exposed, the engine will stop due to air entering the fuel pump. [. . . ]