Suppose you are a boater and want to purchase a new engine for your boat because your boat engine is getting old and not working properly. You go outside and wander in the market, later sometime you find a shop where engines are placed. 

Without knowing that the engine which is fixed in your boat is a marine engine. You go inside the shop and ask for your boat engine to the seller. Then you notice peoples starts laughing who stand around you and whispering why this guy came here if he doesn’t know about his boat engine. I think it may be a shameful moment for you. But this is common, most people don’t know about that.

So it is important to know about the difference between the  marine engines and automobile engine.

It is one of the frequently asked questions, what is the difference between a marine engine and an automobile engine and why an automobile engine is cheaper than a marine engine, many people who use boats are unknown about the difference between marine engine and automobile engine, and their related parts. So in this, we will tell you about their differences as well as their work and functions. 

The marine engine is used in those machines, which are used to travel in river ways and seaways. Marine Engines are expensive because they are not easily available in the market like automobile engines.

On this page we will tell you, so let’s begin.

We will cover :

• Difference between the marine engine and automobile engine.
• Automobile Engine

• Types of Automobile Engine
• Work of Automobile Engine
• How Automobile Engine work.
• Marine engines

• Types of Marine Engine
• Work of marine Engine
• How Marine Engine works.

Difference between the marine engine and automobile engine.

Automobile engines are used in vehicles like cars, trucks, and motorcycles, while marine engines are used in ships, yachts, boats and submarines. 

Marine engines are cheaper than expensive than the automobile engines because it takes more cost while making a marine engine than an automobile engine.

Normal HP(horsepower) of a vehicle is 120HP-130HP, while the normal boat has 125HP-200HP. The value of one horsepower(HP) is equal to 746 watts.

Differences in parts of the  engine.

Marine Engine Parts. 

Bedplate: Two parallel blade run across the engine for two stroke engines.

Camshaft: it’s sets are fitted on to the camshaft hydraulically. 

Frame box: they secure bedplate and support cylinder block by carrying crosshead.

Piston crown:  they are especially made to vary thermal and mechanical stress while transferring the combustion force to the piston rod.

Liner: it is a thin metallic cylinder placed on  the upper part of the cylinder block. While heating of the cylinder liner it allows to go downward.

And many more parts which is installed in marine engines.

Automobile Engine Parts.

Spark plug: supplies the spark to ignite fuel.

Valves: intake valves take air in and exhaust valves out the fumes.

Connecting rod: Connecting rod connects the piston to the crankshaft.

Sunmp: it is surrounded by crankshaft. It hold oil inside, which collects in the bottom of the sump

And many more parts installed in automobile engines..

Automobile Engine

Automobile engines are those engines which are specially made by mechanical engineers for running vehicle (car, scooter, motorcycle, bus, truck) in road. These engines can run by fuels(petrol, diesel and CNG) only. You can find automobile engine in the market easily.

Types of Automobile Engine.

• Diesel engines.

          It runs on petrol and diesel.

• Gasoline engines.

It runs on CNG(compressed natural gas) gas.

Work of Automobile Engine

They produce motion by burning gasoline in metallic cylinder with oxygen, There are various kinds of engines and they work different types. Like car has different engine, truck has different engine and motorcycles has different . The engine is the main part of the vehicle. It partially converts the energy from the combustion to work. It converts the chemical energy into mechanical energy by which vehicle run. 

Where chemical is stands for fuel(petrol, diesel and CNG).

How Automobile Engine work.

• Intake. The process in which fuel is taken with the air and then included into cylinder.
• Compression. The fuel air mixture after the piston compression ignites the spark 
• Power stroke. Compression of the air fuel mixture for the preparation of the ignition.
• Exhaust. The smoke which is taken out by the engine while running.

Marine Engine.

A marine engine is also  called by the name of Marine automobile Engine. This engine is different from automobile engines because it uses in the ships, boats, yachts and submarines. They are specially designed to use in marines. In simple words the main engine that drives the ship is a marine engine.

The upper engine is a simple boat or yacht engine. The ships and submarines have very large engines.

Work of marine Engines:

A marine engine work is to generate mechanical power by which a ship, boat or a submarine can run. 2 stroke and 4 stroke both the engines are used in marine industry. 

Where 4 stroke engine provide high speed, other side 2 stroke engine has very low speed than 4 stroke. Mostly the four stroke engine is used in patrolling ships of Navy and Coastguards because of the good speed. 

Types of marine Engines.

There are four types of marine engines.

• Diesel engines. Same as the automobile engine, marine engine also run on  diesel. It can run by petrol too, if its length is below than 35 feet.
• Steam turbine. It extracts thermal energy from pressurized steam for working on rotating output shaft. Steam turbine also use in airplanes and missiles to generate electricity.
• Gas turbine. It is a combustion engine which is used to convert natural gas and other fuels into mechanical energy. 

How Marine (Boat) Engine Works:

There are no major differences in the working function of automobile engines and marine engines. 

• To generate power, fuel burns the cylinders.
• After the burning fuel gas, its piston moves back and forth.
• The piston rod changes the crankshaft, moving back and forth of the piston (rotating) into motion-and-round (rotary) speed.
• Crankshaft changes the main drive shaft running under the long spine of the motor.
• A gearbox of the drive shaft changes vertical motion into horizontal motion.
• The propeller enabled by the spinning gear horizontally give power to boat through the water.

This is how the marine engine and the automobile engines are different from each other.