ignition lag is increased, causing detonation, whichresults in rough operation. This may cause the engine tostall.If the water temperature is higher than normal, theengine may not cool properly and may suffer heatdamage. Water temperature is controlled primarily by athermostatic valve (thermostat). The thermostatnormally operates with a minimum of trouble. High orlow cooling water temperature may indicate amalfunctioning thermostat. But before you remove thethermostat to check it, check to see whether the impropertemperature may be caused by an insufficient engineload or an inaccurate temperature gauge.When you suspect that the thermostat is notoperating properly, remove it from the engine and testit. Use the following procedure to test the thermostat:1. Obtain an open-topped container such as abucket or a pot.2. Heat the water to the temperature at which thethermostat is supposed to start opening. Thistemperature is usually specified in the appropriatetechnical manual. Use an accurate thermometer to checkthe water temperature. Use a hot plate or a burner as asource of heat. Stir the water frequently to ensureuniform distribution of the heat.3. Suspend the thermostat by a string or a wire sothat operation of the bellows will not be restricted.4. Immerse the thermostat and observe its action.Check the thermometer readings carefully to seewhether the thermostat begins to open at therecommended temperature. (The thermostat andthermometer must NOT touch the container.)5. Increase the temperature of the water until thespecified FULL OPEN temperature is reached. Theimmersed thermostat should be fully open at thistemperature.Replace the thermostat if it does not open when youtest it, or if the temperatures at which the thermostatopens and closes vary more than allowed from themanufacturer’s specifications.The Fulton-Sylphon automatic temperatureregulator is relatively trouble-free. The unit controlstemperatures by a valve that bypasses some wateraround the cooler. This system provides a full flow ofthe water, although only a portion may be cooled. Inother words, the full volume of cooling water iscirculated at the proper velocity, which eliminates thepossibility of steam pockets in the system.Usually, if the automatic temperature regulator failsto maintain cooling water at the proper temperature, itsimply needs to be readjusted. However, the element ofthe valve may be leaking or some part of the valve maybe defective. Failure to follow the proper adjustmentprocedure is the only cause for improper adjustment ofan automatic temperature regulator. Check and followthe proper procedure in the manufacturer’s technicalmanual issued for the specific equipment.Adjust the regulator by changing the tension of thespring (which opposes the action of the thermostaticbellows) with a special tool that turns the adjusting stemknob or wheel. Increasing the spring tension raises thetemperature range of the regulator, and decreasing itlowers the temperature range.When you place a new valve of this type intoservice, you must take a number of steps to ensure thatthe valve stem is the proper length and that all scalepointers make accurate indications. Make alladjustments according to the valve manufacturer’stechnical manual.Obstruction in the Exhaust SystemThis type of trouble seldom occurs if properinstallation and maintenance procedures are followed.When a part of an engine exhaust system is restricted,there will be an increase in the exhaust back pressure.This may cause high exhaust temperatures, loss ofpower, or even stalling. An obstruction that causesexcessive back pressure in an exhaust system isgenerally associated with the silencer or muffler.The manifolds of an exhaust system are relativelytrouble-free if related equipment is designed andinstalled properly. Improper design or installation maycause water to back up into the exhaust manifold. Insome installations, the design of the silencer may causewater to flow into the engine. The source of water thatmay enter an engine must be found and eliminated. Thismay require replacing some parts of the exhaust systemwith components of an improved design or may requirerelocating such items as the silencer and piping.Inspect exhaust manifolds for water or symptoms ofwater. Accumulation of salt or scale in the manifoldusually indicates that water has been entering from thesilencer. Turbochargers on some engines have beenknown to seize because salt water entered the exhaustgas turhine from the silencer. Entry of water into anengine may also be detected by the presence of corrosionor of salt deposits on the engine exhaust valves.3-32
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