3.3 Installation of air inlet system Correct design and installation of the air intake system will be one of the key parameter to achieve optimum engine performance. Opening of air inlet system should be arranged outside the engine room to ensure fresh air availability to the engine. Sharp curves and bends should be minimized. Using of sharp bend (elbows) in the system will create air flow restriction; use large arc bends instead. The inlet air filter should be provided with an additional protective cover to prevent ingress of water and dirt into system during rainy season.
To take advantage of air flow during boat movement; opening of the air inlet entry should be preferably faced towards the front end of the boat. 3.4 Installation of exhaust system The external exhaust duct should be fabricated with steel pipe. Using of sharp bend (elbows) in the system will create restriction in exhaust gas outlet; this will develop excessive back pressure in the system, resulting in poor engine performance. The complete exhaust ducting should be properly supported and fixed to the hull of the boat. Pay attention to expansion bellow while installing the ducting; ducting weight should not be exerted on the expansion bellow.
After installing the system, make sure the back pressure is within the limit. Maximum allowable back pressure in the exhaust system is 6KPa. Exhaust system surface temperature is relatively high during operation of engine. Avoid installing the exhaust pipe near flammable objects, so as to prevent any fire accidents or injury to the working personnel. It is advised to provide adequate heat insulation to the external exhaust system surface. Opening of the exhaust gas outlet should preferably facing rear end of the boat. The exhaust outlet face should be minimum 1.5 Meters higher than the air inlet opening. Refer schematic diagram of figure 3.3. Figure 3.3 8