4 Yamaha two-stroke outboard, Introduction MODEL: YAMAHA (Yamaha) 4 hp two-stroke models: 4ACMHS Displacement: 83cc Engine type: two-stroke / cylinders: one oil supply: Random premixed fuel tank: built-in propeller pitch : 7 "aluminum stern plate height (mm mm): 445 Cooling system: water-cooled Starting system: manual propeller Maximum output power: 2.9KW / 4 hp Max Fuel: 2.2/L/h Weight (kg): 21 Spare Parts: Yes Stalls: forward - neutral - reverse water-cooled two-stroke pistons are referring to two trips up and down. two stroke engine combustion cycle concise, excellent acceleration, faster throttle response and high power, light weight features. Yamaha marine engines with stable performance, high-powered, low fuel consumption, low emissions and other characteristics of two-stroke engine advantages and disadvantages of A, Benefits: * a turn each outbreak of a second, so the smooth rotation. * No valve, fewer parts, so cheap and easy maintenance. * reciprocating inertia force generated small. vibration and low noise. * Compared with the four-stroke engine, the speed is the same power. * Compared with the four-stroke, there are times the explosive power So in the same volume, the same as if the mean effective pressure, the power of 2 times (actually 1.7). B, Disadvantages: * intake and exhaust process time is short, the fuel loss is large. * a wall of the cylinder side port, where easy access to the piston ring wear. * The exhaust port on the cylinder, so easy to overheat. * Slow unstable. * oil consumption more. ④. four-stroke engine advantages and disadvantages A, advantages: * intake, compression, expansion (outbreak), exhaust each process each individually, it is reliable, high efficiency, good stability and low speed to high speed range (500 ~ 1000rpm or more). * does not exist as two-stroke engine The blow-by gas return loss, low fuel consumption. * low running smoothly, relying lubrication system, easy to overheat. * intake process, the compression process for a long time, volumetric efficiency, mean effective pressure is high. * heat load smaller than the two-stroke engine Do not worry deformation, ablation problem. displacement, can be designed into high-power engine. B, Cons: * Valve Valve complex, multi-component, maintenance difficulties * Mechanical noise A, two-stroke piston engine works up from the bottom dead point motion only, it will complete the intake and compression work process, the first part of a piston stroke reciprocating piston downwardly from the top dead point motion only, it will complete combustion expansion (for power) and exhaust work, and belonged to the second reciprocating piston stroke when the piston upward from the bottom dead center point of the movement ended all closed ventilation and exhaust ports, then the exhaust and ventilation process is terminated, the cylinder fresh combustible mixture compression will begin at the beginning, while upward movement of the piston, the piston below the crankcase volume gradually increases, the pressure drop in the crankcase and a vacuum degree, when the degree of vacuum in the crankcase reaches a certain level, the reed valve automatically opens, the carburetor atomized fuel mixture is drawn into the crankcase when the piston continues upward movement, at the point to be close to the top dead center, the spark plug issue, which has been compressed combustible mixture to ignite. At this point the rapid expansion of burning gases, the temperature of the combustion chamber and the sharp rise in pressure, forces the piston downward, that is, through the piston rod, crankshaft as useful work. piston bottom dead center from the top dead point moving, the crankshaft The pressure inside the decrease of volume with the reed valve will gradually automatically closes and the combustible mixture into the crankcase gas started to be pre-compressed when the piston down to the exhaust port is open, gas will through the exhaust port, the exhaust pipe, muffler into the atmosphere when the piston and then continue down to the ventilation port is turned on, the crankcase is pre-compressed fresh combustible mixture then through ventilation port into the cylinder and drive cylinders further discharge of waste within, a process called scavenging process so that the engine will complete a cycle of work. B, four-stroke engine works the first stroke of the intake stroke: the piston at TDC crank angle before a specified time, the intake valve opening, the combustible mixture is sucked into the cylinder when the piston downwardly from the top dead point motion only, the exhaust valve in the top dead center of a predetermined crank angle when closed and the cylinder volume above the piston increases, a vacuum degree of the cylinder a combustible mixture continues through the suction intake valve when the piston line to the next point for a specified crank angle when the intake valve closes and the air intake end of the working process of the second compression stroke trip: Pistons ended up from the bottom dead point motion, when the inlet end of the working process, intake and exhaust valves are in the closed state, when combustible gas mixture within the cylinder begins to be compressed. third stroke combustion stroke expansion work : the compression stroke, when the piston top dead center prior to the upstream of a specified crank angle when the spark plug electrodes, to be compressed combustible gas mixture to ignite. burning of the combustible mixture within the cylinder temperature and pressure rise sharply high temperature and high pressure piston pressure in this role, and then from the top dead point downward movement ended and driven by a connecting rod and crankshaft rotation for useful work. fourth stroke exhaust stroke: the combustion expansion stroke, when the piston is OK to the next stop point before a specified crank angle, the exhaust valve open, the exhaust gas is discharged through the exhaust valve starts. crankshaft continues to rotate, and then push the piston upward from the bottom dead center BDC movement launched the exhaust cylinder. This exhaust process until the piston top dead center line after a specified crank angle, the exhaust valve is closed when the termination Tel 13262641289 Mahon Customer qq1359499595