2007 Yamaha Engines FourStroke F250 HP

2007 FourStroke F250 HP

Variable Camshaft Timing on the new F250. The ECM (Engine Control Module) varies camshaft timing based on engine rpms, maximizing intake and exhaust efficiency. The result? Optimal combustion, greater volumetric efficiency - and a full 16% gain in torque in the 2000-3500 rpm range, where you really need it.

Electronically-Controlled Single Throttle Valve precisely controls the air flow through the surge tanks in to the long tube intake tracks. The air silencer box reduces intake air noise for whisper quiet operation. The long tube intake tracks are tuned to increase air flow which boosts low end and midrange torque and performance.

Multi-Port Fuel Injection 6 individual fuel injectors provide the precise amount of fuel for each individual cylinder. Optimal fuel atomization provides better combustion, further enhancing performance and fuel economy.

Exhaust Pressure Reduction System reduces exhaust pressures while cooling the hub on the propeller. This process increases hp output while simultaneously increasing propeller durability. Another Yamaha innovative performance and reliability feature.

Large Radius Diameter Intake and Exhaust valves The intake tracks are engineered to deliver the air and fuel more directly into the combustion chamber. This design allows additional space for the intake and exhaust valves to have an increased radius which greatly increases volumetric efficiency. The intake valves also have larger valve lift for increase top end performance.