Two Stroke Series - Features & Benefits Our Two Year Limited Warranty protects every Yamaha Two Stroke. Precision Blend™ Oil Injection on models 40hp and up, automatically injects just the right amount of oil into each individual intake based on current engine load and speed, to optimize performance and reliability. Loop Charging increases combustion efficiency to optimize performance and fuel economy. The Front-Mounted Freshwater Flush Device makes it easy to completely flush the engine, in the slip or at home. Maintenance-Free CD Ignition provides automatic spark advance to resist plug fouling and make starting easy. The Engine Sensing Warning Sysytem alerts you to overheating, over-revving and low oil situations. Yamaha's ACP-221 Paint Process provides a 5-layer barrier against corrosion. Stainless Steel is used for the drive, prop and shift shaft for maximum durability. Power Trim / Tilt maximizes hole shot, acceleration and top-end speed. Yamaha’s 100:1 Gas/Oil Premix Ratio on portable models dramatically reduces smoke, odor, fumes and plug fouling. It protects your engine and cuts your oil expense in half. Yamaha's Loop Charged, Pulse-Tuned 3-cylinder design on midrange models delivers cleaner, more complete combustion for improved midrange performance and fuel economy.