Yamaha - Jet, pilot (#37.5) - 7CU-E4142-37-A0Yamaha Pilot Jet #37. 5 Carburetor Fuel Metering Component 7CU E4142 37 A0 Overview Pilot jets are small, but they make a big difference in how an engine behaves at idle and low throttle. When one gets clogged or worn, youll notice it right awayrough idle, stalling, or sluggish response off the line. Ive cleaned plenty, but sometimes replacing it is the only way to get things running right again. When its dialed in, the engine idles smooth and