How To Convert Car Engine To Boat Engine?

There is a big difference between the features of a car engine and a boat engine. It is not easy to change a car engine into a boat engine, but not impossible. With certain changes, you will learn how to convert car engine to boat engine.

 You’ll need the following tools to modify the car engine into the boat. 

  • A Water-Based Cooling Exhaust
  • A Water Pump Specialized for Marine Uses
  • Carburetor Tilter 
  • A Flame Catcher for Carburetor
  • Solid Brass Plugs
  • Special Engine Mounts
  • Oil Filter Modification Tools
  • Exhaust Elbows for Marine Use
  • Water Cooler Cover Plates 
  • Extensions for Starters

Alterations required to convert the car engine into boat engine

  • Broad power camshaft for boat engine required to replace narrow one.
  • Replace air cleaner with flame catcher 
  • Instead of ignition alternators, use ignition-free alternators 
  • The water-cool exhaust will replace the air exhaust system of the car.
  • Use brass plugs; remove the steel plugs from a car engine.
  • Special water pump for boats and marines.

350 engine conversion to marine?

The Chevy 350 engine is a 350 cubic inch small block; 350 engines are known for their better output and ease of maintenance. 

Can we convert 350 engines to marine?

The answer is yes, As a marine engine is like an automotive car engine. With little changes and modifications, the alterations will prove awesome.

Need to do alterations in the following area : 

Cooling system, Electric system, Exhaust system, and oil/fuel. 

  1. You will start from the camshaft and replace the camshaft of the car engine with a broad power camshaft. The boat does not have gears; it has fixed movements of forward and reverse; the broad camshaft will help normalize the speed in all directions.
  2. In marine engines, water pumps open that work in water, so use ceramic seals and Car motors in a boat. Stainless steel backing plates for efficient work of the water pump.
  3. You will replace air-cooled exhaust with water-cooled exhaust.
  4.  Organize A complete sealed electrical system in marine 
  5. Arrange Different fuel systems. Marine engines have carburettors with fuel bowls that can resist vibration and pitch on boats. You will convert the 350 engine into a marine with active enhancement.

Mercruiser 350 vs. GM 350

The difference between Mercruiser and GM 350 car engine 

  1. Mercruiser  engines survive in the water while GM 350 are for roads.
  2. Mercruiser engines have one gear for reverse; forward cars with four 3-Mercruiser engines are not used daily, while GM350 engines are used frequently.
  3. The 4-Camshaft of the Mercruiser is broader, while GM350 has a narrow camshaft. 

Alternators and distributors in marine engines are different compared to cars.

  1. The marine engine uses low-end torque, while the car engine uses high RPM horsepower.
  2. 6- Mercruiser 350 includes a water-cooled exhaust system, while GM 350 includes an air-cooled exhaust system.
  3. Mercruiser include a flame catcher that minimizes the risks of explosion from backfire, while cars include air cleaner.

Read: Dual VVT-I Engine: More Horsepower and Fuel Economy

Making a V6 car engine into a marine engine?

Car engines are different from boat engines in many ways. They both share different features, working, and components. It is not impossible to convert a V6 engine to Marine, But it will need several alterations. 

And money, as you will need to buy a few things. Necessary changes that are irresistible. Always buy the required material from Marine shops and distributors. They have reasonable prices.

Marine engines include different features of running speed as compared to V6, as V6 has speed decreasing, increasing, and gear transmission system. 

You will change the camshaft to update the boat engine with a broad power camshaft. 

As V6 has sparking alternators, replace them with ignition-free alternators Replace the sparking alternators with ignition-free alternators. 

A mechanism that sucks up all the heat caused due to the ignition. Replace the exhaust system of v6 with a water-cooled system for marine. 

In V6, the system does not pump water inside the engine air cleaner of V6 into the flame catcher. These changes will give you a small boat for your use. 

Can a car engine be used in a boat?

Simply if anyone uses the engine of a car for a boat engine, it will not work as 350 or gasoline vehicles engines are recommended for boats but with alterations that are mandatory to do . Otherwise, the car engine won’t work in boats.

One can understand the big difference between cars is that roads and boat engines will work on water. 

Obviously, the features of both engines will be totally different, and their component mat differs. A car engine is only used after spending money to buy the required technical and mechanical things or products that are essential for marines. 

Read: Dual VVT-I Engine: More Horsepower and Fuel Economy

Are car engines and boat engines the same?

The engines are not the same as per their environmental conditions and situations. Their building, structure, features, components, working, and problems are different. 

A car engine uses a little p[ortion of their horsepower, while a boat engine is heavy-duty and at full throttle all the time. Marine distributors, starters, and alternators are different from a car engine. 

In marine all these have special screen systems. Boats are not in regular use as compared to cars, so the engines of cars are in more use daily and need maintenance regularly.

Can you put an LS motor in a boat?

A special kit is required to swap the systems. These engines use electronic control units to process the fuel and ignition system.GM Ls 1 to 6 series engine uses the CAD-engineered engine swap system to mount a GM LS series engine into a famous jet-driven power boat into these electronic control units. These engines can’t work without an electronic system.

What is the difference between marine engines and car engines?

Marine engines are heavy duty, Marines are for water environments, while cars engines are for dry environments. The camshaft of a car engine is narrow band, and marine engine camshaft ate broad power. 

Marine engines are constantly fully throttled to move in the water, while car engines use a portion of their horsepower.  Car engines use air exhaust systems, and marine engines use water-cooled exhaust systems. 

Flame catcher is the most important feature of a marine, while in car engines, you will see air cleaner. 

Read: How To Get A Cat Out Of A Car Engine?

4.3 truck engine in the boat

The 4.3 engine is a good performance engine with great power/energy and torque, the most reliable engine for the boats if you want to convert. 

It is a fuel-efficient engine. With few alterations the engine in the boat will work well. 

  • Camshaft for speed of the boat 
  • Exhaust system for boat, water-cooled.
  • Flame catcher system 
  • Water pump 
  • Brass plugs for better response, adjust the oil filters, mounting of the engine. 

Best marine engine conversion kit

Efi kit (marine kit ) 

Electronic fuel injection replaces the need for a carburettor that mixes air and fuel.  It throws fuel directly into an engine’s cylinder using electronic controls.

This kit allows carbureted Marine applications easy to convert in EFI.

A few considerations are needed for Marine applications that are included in this Kit.

The first one is Moisture resistance which takes the temperature of Marine applications different from car engines and automotive applications.

The facility of installing the o2 sensor that is required in an existing marine exhaust system,

It has been easy now to convert the boat from a carburettor into an EFI Kit.

Can you put a truck motor in a boat?

Truck Tractors and boat engines are of the same family. The engines of trucks and trailers are not made of 100 per cent continuous power output capacity. 

If it would, then it would be working for Marines too. During starting and landing requires 100 per cent power output. 

Their differences come from the same family. If the truck had 100 per cent power output capacity, it would be useful for  Marines.

How to convert an engine to marine?

If your car is not in use and you want a marine. You can convert with several alterations. You will need to change the systems as both are technically different. Their fuel intake system is totally different. With the given installation you will do for the marine.

  • Cooling system
  • Freeze plugs( Brass plugs)
  • Cam change) broad power camshaft )
  • ALL electrical parts
  • Fuel Pump
  • Carb or fuel injection

Is the Honda car engine in the boat?

Honda Marine is part of “Honda’s Power Products” They have made four-stroke outboard marine engines. They were the second U.S. company to build a four-stroke marine outboard engine. They manufactured the first marine engine in 1964.

Honda car engines are different from marine engines; Honda makes special marine engines on the same engine blocks they use in cars. It is impossible to convert the Honda car engine into a boat, but with many changes, technical and electrical, you will; install many systems to update the Martine.

Cooling system

  • Freeze plugs( Brass plugs)
  • Cam change) broad power camshaft )
  • ALL electrical parts
  • Fuel Pump
  • Carb or fuel injection


People fond of boating and fishing can’t afford the high expense of purchasing a marine. They can convert the engines. They can replace their extra or second-hand good quality engine from a reliable mechanical shop and install it in a marine but with many changes. 

Purchasing of new products will be required to update the Marine systems discussed above. So pint is within a low budget. Anyone can afford a marine. Just they have to visit the markets. Full knowledge of engine Requirements for a marine engine. 

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