Re: 2 Stroke? 4 Stroke? WHAT DOES THAT MEAN??
Some other important things...
<br /><br />The 4 processes for both engines are the same....Intake, compression, power, exhaust. The 4-stroke (4-cycle) performs this sequence in 2 revolutions of the crankshaft. The 2-stroke (2-cycle) performs this same sequence in 1 revolution of the crankshaft. The 2-stroke accomplishes this by using intake and exhaust transfer ports that enter and exit the cylinder. The 4-stroke uses mechanical valves.<br /><br />The 4-stroke will have an internal pressurized oiling and filtration system. The 2-stroke will not.<br /><br />The 2-stroke will have a cage reed pedal intake which functions as as a result of engine resonance, and intake and backpressure forces. The 4-stroke has a completely mechanical lubricated valve train assembly (cams, lifters, rods, and usually multiple valves per cylinder), which is operated by a oil bath gear drive or a belt.<br /><br />2-stroke outboards don't have variable exhaust timing and therefore require a tuned exhaust system, which in effect narrows the powerband.<br /><br />The intake and exhaust design of 2-strokes inherently allow for poor scavaging (forcing out all exhaust gases and burning all intake fuel completely), which makes the engine less efficient and more environmentally unfriendly. It also makes them inherently produce more noise.<br /><br />2-stroke
outboards don't always "rev higher". Most 4-strokes, like Yamaha and Suzuki's 4-strokes, actually rev higher than their 2-strokes.<br /><br />4-strokes usually come with a better (longer) warranty.<br /><br />Both are great outboards. Cost, weight, dealer service, emissions, longevity, resale, economy, performance, and overall enjoyment are usually the determining factors between the two.<br /><br />Hope this helps.