Equipment Operator, these troubles are easy to detect without too much checking and testing. The supervisor  must,  however,  make  the  mechanics aware  that  there  probably  was,  in  addition,  an actual or contributing cause to the power failure. The supervisor must train the mechanics to look for  this  cause  while  making  repairs.  Unless eliminated, this may be the cause of major trouble later on. Too often, troubles concerned with power loss occur within the engine and are not easily found. It is these hard-to-find troubles, with little or no visual  indication,  that  keep  the  CMs  busy.  An operator may notice a decided power loss in the equipment and, because there is excessive smoke coming  from  the  exhaust,  report  the  trouble  as improper carburetion, or, in the case of a diesel engine,  as  injector  trouble. An  inexperienced  mechanic  may  notice  an increased engine temperature in addition to the exhaust smoke and diagnose the loss of power as improper valve action or as trouble in the cooling system. The diagnoses are comparatively simple through  visual  indications.  But,  as  a  CM1,  you know  that  there  are  many  causes  of  power  loss that  have  little  or  no  visual  indications.  Examples are   incorrect   ignition   timing,   faulty   coil   or condenser, defective mechanical or vacuum spark advance, worn distributor cam, or slipping clutch. Any  of  them  can  cause  a  power  loss. After  a  deficiency  has  been  located  in  an engine, it is usually easy to make the necessary corrections  to  eliminate  the  conditions  causing  the deficiency.  Careful  analysis  and  straight  thinking, however,  are  often  needed  to  find  the  cause  of engine  deficiencies.  If  a  supervisor  has  a  thorough knowledge of the basic engineering and operating principles of an engine, his or her job of training the mechanics will be easier and more interesting. In diagnosing engine deficiencies, the supervisor must  never  jump  to  conclusions  and  make  a decision  on  the  nature  of  repairs  to  be  made before  being  sure  that  what  will  be  done  will eliminate   the   trouble.   The   mechanics   must be   able   to   interpret   the   engine   instrument indications  as  well  as  use  the  proper  testing devices. Furthermore, they must be able to road test the equipment to determine whether repairs have  been  made  satisfactorily  and  whether  a  part or several parts should be adjusted or replaced. Besides, the mechanic must know when and how to make emergency adjustments for every unit on the engine. It may seem required  of  a that  some  of  the  qualifications good  mechanic  point  to  the know-how  of  an  automotive  engineer.  However, no  one  person  can  know  all  about  engines  and also be an expert in repairing all kinds of powered equipment used by the SEABEEs. For instance, if  the  checks  or  instrument  tests  indicate  some internal trouble in a magneto, carburetor, or fuel injection  unit,  the  repairs  should  be  made  by mechanics  who  have  experience  or  have  been specially trained to use the equipment to do the particular  job  at  hand.  It  is  the  supervisor  who will  be  expected  to  have  the  answers  to  all the   questions   asked   by   less   experienced   me- chanics. The three basic factors that affect an internal combustion  engine’s  power  are  as  follows: COMPRESSION,   IGNITION,   and   CARBURE- TION.  In  the  diesel  engine,  fuel  is  injected  into each cylinder, and ignition depends on the heat of  compression;  in  the  gasoline  engine,  ignition and  carburetion  are  independent.  In  both  engines, of  course,  proper  action  and  timing  of  all  three factors  are  necessary  for  the  engine  to  produce its  rated  power. It  is  obvious  then  that  an  engine  runs  and develops   rated   power   only   if   all   of   its   parts function or operate as they should. If any of these parts  wear  or  break,  requiring  replacement  or adjustment,  the  performance  charts  and  engine specifications   are   “tools”   that   will   help   the mechanic  to  bring  those  parts  back  to  their original  relationship  to  each  other. There   are   more   factors   NOT   directly associated with engine working parts that must be   considered   in   correcting   engine   power losses. OPERATING  CONDITIONS  can  affect  en- gine power. For example, the usable horsepower of  an  engine  is  reduced  by  the  number  of accessories   it   must   operate.   If   the   engine   is required  to  provide  power  for  lifting  operations at the same time it is delivering power to wheels or  tracks,  the  engine  may  be  overloaded  and may  not  be  able  to  develop  its  rated  rpm;  con- sequently,  the  rated  horsepower  would  NOT  be reached. The  effect  of  ALTITUDE  on  engine  power must also be considered. As a rule, 2 1/2 percent of  the  output  of  an  engine  is  lost  for  every 1,000-foot increase in elevation above sea level. Overheated air entering the cylinders has the same effect on engine power as an increase in altitude. In computing horsepower output, engineers will deduct  as  much  as  1  percent  for  each  10°F  rise in  the  intake  air  temperature  above  a  “normal” temperature  of  70°F. 3-9