YS 50 ST

The YS 50 ST is the second generation of the 50 Series. I have been flying this engine in my Raptor 50 and the power delivery and fuel economy are excellent. I recommend running a Hatori SB-15 on this engine.

Break-in Procedure: After running a tank of fuel, bring the helicopter into a hover and look for a solid smoke trail. You should also pay close attention to the sound of the engine. A lean condition will make the engine sound raspy, and a rich condition will gurgle and be unresponsive. At this point you will want to tune the high-end needle until you get a nice smooth run in a hover and top end power.
Most common fuel system problems: Cracked fuel tank: Split at a seam Clunk line hitting back of tank: As fuel line gets older if will stretch and go soft. Fuel line and Fuel line “T”s: Not holding pressure. Silicone Rubber: I have found many engines plugged up with bits of silicone. Diaphragm: Check for cracks or torn around the edges. Regulator Gasket: Plugging up holes for fuel and or pressure. Dirt in Carb: Yes even if you have fuel filters. Using in-line fuel filters is a good way to prevent junk from getting into the carb but remember, anything that can go into the carburetor can make it’s way to the fuel regulator. I have seen the following stuck in regulators and inside engines: Grass, Paint chips, Mud, Silicone Rubber ect…** I recommend using Cool Power 30%, a Hatori muffler and an Enya #3 glow plug. I have found that this combination provides reliability, excellent power, and exhaust note for the 90SR and the 50ST.