Posts Tagged ‘4 stroke outboards’

The motor is the driving force behind a bboat-03oat, which is why it’s important to choose the right one. While there are literally hundreds of different gas motors available, ranging in size, power and utility, nearly all of them fall under one of two different categories: 2-stroke and 4-stroke.

The term “stroke” refers to the motor’s piston movement. In 2-stroke motors, the pistons move with one stroke in each direction. The compression stroke triggers the the combustion of fuel and air, and the return stroke pushes more of the fuel mixture back into the motor.

4-stroke motors differ in their piston movement, as it features 1 compression stroke, a return stroke, an exhaust stroke, and another return stroke. The purpose of the exhaust stroke, which is not used in 2-stroke motors, is to release the spent gas fumes through the exhaust.

In general 4 stroke motors are quieter and use slightly less fuel. Although the 2 stroke motors have significantly reduced the amount of smoke they produce, the 4 stroke motors are a cleaner burning choice. Based on these features most customers that are heavily focused on performance tend to favor the lighter 2 stroke motors whereas the customer looking for a quiet, clean and efficient burning motor such as for pontoon boat applications will lean towards the 4 stroke motor option.

Two-Stroke motors

Technical jargon aside, 2-stroke motors are generally smaller, lighter and more compact than their counterpart, making them a popular choice for small vessels. This is due to the fact that 2-stroke motors don’t require a valve train. Without a valve train hogging up valuable space, manufacturers can produce powerful 2-stroke motors which are small in size.

Not long ago, 2-stroke motors were viewed as fuel-hungry and loud when compared to 4-strokes; however, newer models have tackled this issue by eliminating the carburetor. Modern-day models use a more efficient computerized system, known as a Direct Fuel Injection (DFI), to regulate the ratio of fuel to air in place of a carburetor.

Four-Stroke motors

A typical 4 stroke motor is similar to that of a car or truck. The intake valves bring the fuel and air into the combustion chamber, and the gas vapors exit through the exhaust valve. Due to the presence of a valve train (intake and exhaust valves), however, 4-stroke motors are usually heavier and bulkier than their counterpart.

A 4-stroke motor also feature a complete lubrication system with an oil filter and drip pan. This helps to wick away heat while promoting a smooth operation. On the flipside, though, you’ll have to change the oil on a regular basis – just like you a road-worthy automobile – to keep the motor working in peak condition.

Hopefully, this will give you a better understanding of the differences between 2-stroke and 4-stroke motors. Granted, the gap between the two has closed in recent years, there are still subtle nuances that current and prospective boat owners need to be aware of.