0338078 EVINRUDE ENGINE COVER, Lower, Jo., front

The flat type air cleaner uses a filter paper type element.(b) Cyclone type air cleaner The cyclone type air cleaner uses a filter paper type element.Because of plastic coating and heat treatment, the element is highly resistant to water and oil. Even if it is contaminated, its functions can be regained by cleaning.The intake air is given a spin by the vanes for centrifugal separation of large particles of dust and dirt. Small particles of dust and dirt are filtered out by the filter paper element so that a clean air is drawn into the engine.The standard air cleaner is a single element type, and the double element type can be effective for operation safety under unusual conditions with a lot of dust and dirt.(2) Precleaner The precleaner, coupled with the air cleaner, collects relatively large particles of dust contained in the air drawn in by engine.The air entering the precleaner is made to spin by the guide vanes of the precleaner to centrifugally separate large particles of dust before the air is drawn into the air cleaner. These dusts are collected in the precleaner.(3) Vacuator Valve Centrifuged dust collects at the bottom of the air cleaner. A vacuator valve made of rubber is mounted to the bottom, which pulsates to automatically discharges dust and water when the engine speed is below about 8-0 rpm. Namely when the engine is running at a speed higher than 800 rpm, the negative pressure in the air cleaner keeps this valve closed but when the negative pressure drops as the engine speed decreases, the valve is made to open by rubber action, thereby discharging dust and water.(4) Dust Indicator The dust indicator is mounted near the outlet of the air cleaner.The dust indicator operates on the negative pressure of the air drawn into the engine performing the function of indicating the time to clean or replace the element.If dust is collected in the element, the suction resistance increases. When the negative pressure reaches 7.47 kPa (762 mmH2O), the signal is pulled down against the spring pressure, and the transparent portion of the body changes to red, indicating the time to clean or replace the element.After the element has been cleaned or replaced, depress the reset button on the top, and the signal will return to its original position.* Electrical dust indicator In the electric dust indicator, its electric contact points close at a negative pressure of 6.23 kPa (635 mm H2O) to turn on the warning lamp, indicating to the driver the time to clean or replace the element.(5) Turbocharger The turbocharger utilizes the energy of the engine exhaust gas to feed more air into the engine, thereby offering advantages such as boosted engine power output, thrifter fuel consumption, and reduced engine noise.The exhaust gases discharged from the cylinder of the engine are led through the exhaust manifold into the turbocharger and are accelerated in the turbine housing and are blown against the turbine wheel. Accordingly, the turbine is made to rotate at a speed of scores of thousands of revolutions a minute, and turns the compressor wheel mounted on the same shaft as the turbine wheel. By rotation of the compressor wheel, a larger amount of air than without supercharging is forced into the cylinder of the engine, so a correspondingly larger amount of fuel can be burnt. This increases the effective pressure during combustion (the pressure forcing the piston down) and thus increases the output. The turbocharger can be divided into two basic sections: the turbine wheel that is driven by the exhaust gases and the compressor wheel which forces intake air into cylinders.The shaft connecting the turbine wheel with the compressor wheel is supported in floating type bearings, which absorb vibrations during high speed operation that are caused by slight imbalance of the shaft.The shaft axial load is borne by the thrust bearing. The bearing housing has its inside cooled and lubricated by engine oil to prevent seizure and other troubles of the sliding parts.(Refer to Group 12 Lubrication.)(a) Waste gate mechanismThe waste gate mechanism relieves part of exhaust gases with the engine at high rpm range, allowing it to bypass the turbine wheel. This controls the boost pressure at an optimum level and prevents the turbocharger overrun as well as excessive pressure buildup inside the exhaust manifold. The boost pressure is introduced from the compressor cover through rubber hose to the chamber A of actuator.When the boost pressure applied to chamber A is low, the actuator does not operate and the waste gate kept closed, so the exhaust gas blows the compressor wheel. When the boost pressure applied to the chamber A exceeds the predetermined level, it overcomes the spring force to open the waste gate valve, which decreases the volume of exhaust gas blown against the turbine wheel. This, in turn, reduces the speeds of turbine and compressor wheel to lower the boost pressure.(b) Over-boost valve An over-boost valve is mounted on the air intake pipe. The over-boost valve functions when the boost pressure abnormally increases due to a waste gate valve malfunction. If the boost pressure inside the air intake pipe exceeds a predetermined level, the over-boost valve is forced to open by the pressure to release it in atmosphere. this protects the engine from undue boost pressure. When the over-boost valve is opened, a whistling sound is heard.In such an event, it is necessary to check and repair the turbocharger promptly.2. Specifications
3. Service Standards
3.1 Service Standards Table
(1) Dust indicator (2) T04B turbocharger (3) TD07 turbocharger 3.2 Tightening Torque Table
4. Special Tool
T04B turbocharger 5. Service Procedure
5.1 Removal and installation
5.2 Air Cleaner
Disassembly and reassembly
(1) Cyclone type air cleaner (2) Flat type air cleaner Inspection and cleaning
(1) Blow a compressed air of lower than 685 kPa (7 kgf/cm2) pressure from inside the element along the folds. 1. Avoid striking the element or blow compressed air from outside.2. Do not clean the inner element.3. If the element is heavily contaminated with oil, etc., it must be replaced with