If inspection reveals signs of water in an engine orin the exhaust manifold, take steps immediately tocorrect the trouble. Check the unit for properinstallation. Wet-type silencers must be installed withthe proper sizes of piping. If the inlet water piping is toolarge, too much water may be injected into the silencer.There must be continuous-type water drains on thesilencer. If a silencer has no continuous drain and if theengine is at a lower level than the exhaust outlet, watermay back up into the engine.Dry-type silencers may become clogged with anexcessive accumulation of oil or soot. When this occurs,exhaust back pressure increases, causing troubles suchas high exhaust temperature, loss of power, or possiblestalling. A dry-type silencer clogged with oil or soot isalso subject to fire. Clogging can usually be detected byfire, soot, or sparks coming from the exhaust stack Anexcessive accumulation of oil or soot in a dry-typesilencer may be due to a number of factors, such asfailure to drain the silencer, poor condition of the engine,or improper engine operating conditions.Insufficient Intake AirInsufficient intake air, which may cause an engineto stall or stop, may be due to blower failure or to aclogged air silencer or air filter. Even though all otherengine parts function perfectly, efficient engineoperation is impossible if the air intake system fails tosupply a sufficient quantity of air for completecombustion of the fuel.CLOGGED AIR CLEANERS AND SILEN-CERS.—Sometimes an engine will fire erratically ormisfire because of a clogged air cleaner or silencer. Aircleaners must be cleaned at specified intervals, asrecommended in the engine manufacturer’s technicalmanuals. A clogged cleaner reduces the intake air,thereby affecting the operation of the engine. Cloggedair cleaners may cause not only misfiring or erratic firingbut also such difficulties as hard starting, loss of power,engine smoke, and overheating.When you clean an air cleaner element, if you use avolatile solvent, be SURE the element is dry before youreinstall it on the engine. Volatile solvents are excellentcleaning agents but, if permitted to remain in the filter,may cause engine overspeeding or a serious explosion.Oil-bath type air cleaners and filters cause very littletrouble if serviced properly. Cleaning directions areusually given on the cleaner housing. The frequency ofcleaning is usually based on a specified number ofoperating hours, but more frequent cleaning may benecessary where unfavorable conditions exist.When you fill an oil bath-type cleaner, follow themanufacturer’s instructions. Most air cleaners of thistype have a FULL mark on the oil reservoir. Fillingbeyond this mark does not increase the efficiency of theunit and may lead to serious trouble. When the oil bathis too full, the intake air may draw oil into the cylinders.This excess oil-air mixture, over which there is nocontrol, may cause an engine to “run away,” resulting inserious damage.BLOWER FAILURE.—Troubles that may preventa centrifugal blower from performing its functionusually involve damage to the rotor shaft, thrustbearings, turbine blading, nozzle ring, or blowerimpeller. Damage to the rotor shaft and thrust bearingsusually results from insufficient lubrication, anunbalanced rotor, or operation with excessive exhausttemperature.Centrifugal blower lubrication problems may becaused by failure of the oil pump to prime, low lube oillevel, clogged oil passages or oil filter, or a defectiverelief valve, which is designed to maintain proper lubeoil pressure.If an unbalanced rotor is the cause of shaft or bearingtrouble, there will be excessive vibration. Unbalancemay be caused by a damaged turbine wheel blading orby a damaged blower impeller.Operating a blower when the exhaust temperatureis above the specified maximum safe temperaturegenerally causes severe damage to turbochargerbearings and other parts. Make every effort to find andeliminate causes of excessive exhaust temperaturebefore the turbocharger is damaged.Turbine blading damage may be caused byoperating with an excessive exhaust temperature,operating at excessive speeds, bearing failures, failureto drain the turbine casing, the entrance of foreignbodies, or by turbine blades that break loose.Damage to an impeller may be caused by thrust orshaft bearing failure, entrance of foreign bodies, orloosening of the impeller on the shaft.Since blowers are high-speed units and operate witha very small clearance between parts, minor damage toa part could cause extensive blower damage and failure.Although there is considerable difference inoperating principle and construction between thepositive-displacement blower (Roots) and the3-33
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business