3-18. If the water in the cooling system of  a  diesel  emergency  generator overheats  because  the  thermostat fails  to  function,  what  corrective action  should  you  take? 1. Clean the bellows of the element 2. Adjust  the  tension  of  the regulator  spring 3. Clean  the  freshwater  cooler 4. Replace  the  thermostat 3-19. In  the  Fulton-Sylphon  automatic temperature  regulator,  what  happens if you decrease the spring tension? 1. The  velocity  of  the  cooling water  decreases 2. The  temperature  range  of  the regulator  increases 3. The  temperature  range  of  the regulator  decreases 4. The  velocity  of  the  cooling water  increases 3-20. Which of the following troubles in the  engine  exhaust  system  will cause  back  pressure? 1. Obstruction  in  the  combustion space 2. Thermostat  failure 3. Restricted   exhaust 4. Restricted  oil  filter 3-21. After  being  cleaned,  most  oil bath-type  engine  air  cleaners should be refilled to what level? 1. To the full mark 2. Slightly  above  the  full  mark 3. To  the  halfway  mark 4. Slightly less than the halfway mark 3-22. Which  of  the  following  conditions can damage the turbine blading of a turbocharger? 1. Foreign  objects 2. Bearing  failure 3. Overspeeding 4. Each of the above 3-23. Which  of  the  following  conditions will  NOT  cause  scoring  of  blower parts? 1. Dirty lube oil 2. Worn  gears 3. Improper  timing 4. Improper  end  clearance 3-24. How  can  you  determine  whether blower  rotor  gears  are  worn excessively? 1. Measure  the  clearance  between the  leading  and  the  trailing edges of the rotor lobes 2. Measure  the  backlash  of  the gear  set 3. Measure  the  clearance  between the rotor lobes and the casing 4. Check the timing of the rotors 3-25. Which  of  the  following  conditions is a major contributing factor to diesel  engine  power  loss,  starting failure,  and  frequent  stalling? 1. High  cooling  water  temperature 2. Faulty  operation  of  the governor 3. Improperly  engaged  jacking  gear 4. Faulty  air-starting  distributor 3-26. If you are checking an engine for a stuck  fuel  control  rack,  what should  you  do  immediately  after disconnecting  the  linkage  to  the governor? 1. Visually  inspect  the  rack 2. Try to move the rack by hand 3. Test  the  return  springs 4. Clean  the  removed  rack 3-27. A  leaking  fuel  injector  may  cause an engine to 1. stop 2. overheat 3. operate  better 4. continue  to  operate  when  you attempt to shut it down 19