Raw water cooled marine engine

Removing the thermostat will make the engine run hotter as most water will take the path of least resistance through the bypass. Locate raw water inlets and close all sea cock valves associated with the system to be cleaned.

There are two main types of cooling apparatuses involved when talking about marine diesel engines.

Raw water cooled marine engine. Raw Water Cooling Systems. RawSea water cooling systems draw water outside the boat seawater or lake water. Water is pumped from the source to engine block then the engine circulation pump forces the raw water go through the engine block and expelled through exhaust manifold.

Raw water cooling systems are relatively simple as the standard cooling system on most Marine Engines. In a raw water system the water is drawn up through the seacock by the water pump. The water flows through the engine and directly out the exhaust.

This cooler water absorbs heat from the engine to help keep it cool. Most newer marine engines use an enclosed cooling system. Cleaning Engine Raw Water Cooling System 1.

Locate raw water inlets and close all sea cock valves associated with the system to be cleaned. Also locate raw water pump and isolate the overboard discharge overboard is normally connected to main exhaust. Once the sea cocks and all drains are closed make sure that there is not a heat.

In the old days many marine engine cooling systems were of the raw-water variety meaning simply that they relied on pumping whatever water the boat was floating in through the engine and pumping it out the exhaust systemsalt water polluted. Whats more it works. Home made raw water cooled manifold for my AD 195M Flange and upper large nut are drilled tapped and fitted with brass hose outlets joined with heater hose.

The big nut is also tapped for the heat sensor. The 1 14 pipe goes right through the 3 with a water inlet drilled into the 1 14 inside the water jacket. Marine Engine Raw Water Cooling Pumps.

INet Marine sells a complete line of raw water pumps. Pumps are available for most Caterpillar Chris Craft Chrysler Commander Crank Mount Crusader Cummins Detroit Escort Skiltec Glastron Indmar Interceptor Isuzu John Deere Kohler Marine Power MerCruiser North American Engine Northern Lights. With a used boat with raw water cooling you will never know if the engine was flushed after every use and unless you remove parts you will not know the amount of corrosion and rust inside.

Removing the thermostat housing is one way to check another is to run the engine if out of the water with a hose attackment and watch for rusty water exhausting. Salt will begin to precipitate out of seawater at approximately 148 F forming deposits on engine cooling passages which ultimately will lead to poor water circulation and overheating. Thus nearly all raw-water-cooled gasoline and diesel marine engines have a 140 thermostat.

The thermostat on several raw water cooled engines Bukh and Yanmar to name two have a dual action. As the engine warms the thermostat opens and simultaneously closes the bypass directing cool water into the engine. Removing the thermostat will make the engine run hotter as most water will take the path of least resistance through the bypass.

There are two main ways engine manufacturers engineer the cooling system on a boat. Raw Water Cooling Systems. This style sucks the salt-water straight out of the ocean through a strainer filter and then cycles it through your engine block.

Water is then usually exited through the exhaust and out the back or below the boat. On a FWC equipped engine raw-water can still enter internally into the engine or transmission through raw-water cooled oil coolers. Raw-water can also get into the engine jacket through the main heat exchanger as well as enter the engine cylinders through leaky raw.

Descaling raw water cooling channels. Salt deposits in the jacket can be a real problem on some marine engines. If you have a raw-water cooled marine diesel engine such as a Yanmar or a BUKH then you will suffer from the same problem that many petrol outboard owners have.

Youll recall from your school days that when acids and alkalies are mixed. In marine engines the raw water by-pass will remain open thus allowing the engine to overheat. Thermostat Opens - thermostats are designed to open gradually as the coolantraw water in the engine blocks heats up allowing hot coolant to pass through the heat exchanger in indirect cooled engines or for raw water to pass through the engine in direct cooled engines and out the exhaust.

Never had a problem with a raw water cooled engine diesel inboards blown 454 hydros V-6 outboards. First boat with a Yanmar fresh water cooled engine which runs great but found it interesting how often the coolant needs to be changed. Read the service manual and says the coolant anti-freeze-water mix is actually caustic to some of the parts.

The term Fresh Water Cooling also termed Closed Cooling can be confusing as compared to Raw Water or Open Cooling Systems as these closed systems circulate antifreeze and not water. Marine Fresh Water Cooling systems are similar to the cooling system in an automobile however rather than a radiator they utilize a heat exchanger and rather than using air to remove the heat generated by the. Today we will be taking a look at a vital piece of this puzzle.

Raw Water Cooling Systems. There are two main types of cooling apparatuses involved when talking about marine diesel engines. Depending on the model your engine will either have an enclosed cooling system similar to that of a car or a raw water cooling system.

Maintenance Raw Water Cooling. Main Concerns Task List Indirect Cooling Fresh Water Cooled Direct Cooling Keel Cooling 1 Clean Thruhull of Anti-Foul Paint and Marine Growth 2 Check Emergency Plug Tied to Every Seacock 3 Check Seacock OpensCloses Smoothly 4 Inspect Raw Water Strainer 5 Service Raw Water Pump Impeller 6 Check and Change Heat Exchanger Anodes. Raw water cooling systems are relatively simple and the standard cooling system on most Marine Engines.

The raw water pump in most cases is inside the outdrive. On larger engines and inboard engines the raw water pump is located inside the boat and is driven by a v-belt or directly off of the crankshaft. The danger is using salt water as a coolant in your engine.

Salt water can be highly corrosive. Shut off the engine. Turn off the fresh water.

It is very important that you do not try to inject water into the system with the engine off and the seacock closed as this could cause some problems. There is a potential for damage to the water seal in the Raw Water pump among other things. Raw water cooling systems draw water from outside the boat seawater or lake water.

Water is pumped from the source to the engine block then the engine circulation pump forces the raw water thru the engine block and the water is expelled thru the exhaust. Raw water cooling systems are relatively simple and the standard cooling system on most marine Engines. The raw water pump in.

I shut it down and after sailing for a few hours on restarting no water. The raw water intake is not plugged. I then removed the water pump.

Water gets to the pump and the impeller looks in good shape. I am curious about the black flow of water This is a new boat to me and does not yet have a raw water strainer. The engine is a Yanmar 2gm.