TM  5-6115-323-14 Table 4-1. Organizational Preventive Maintenance Checks and Services W  -  weekly  (40  hours) S - Semiannually (500 hours) M - Monthly (100 hours) H  –  Hours  (as  indicated) PROCEDURES EQUIPMENT ITEM INTERVAL I T E M CHECK FOR AND HAVE IS NOT READY NO. INSPECTED REPAIRED  OR  ADJUSTED AVAILABLE WH AS  NECESSARY 1 50 Lubricating  Oil Change oil every 50 hours of operation. 2 50 Fuel Filter Inspect fuel filter every 50 hours of  operation.  Clean  as  necessary (para 4-17 and Fig. 4-7, TM 5-2805-257-14). Section   V.   Troubleshooting 4-11.  General This  section  contains  troublshooting  or  mal- function infornmtion and tests for locating and correcting meet of the troubles which may develop in  the  generator  sets.  Each  malfunction  or  trouble symptom  for  an  individual  component  unit  or system is followed by a list of test or inpections necessary  for you to determine probable causes and suggested corrective actions for you to rem- edy the malfunction. 4-12.  Troubleshooting a. This manual cannot list all possible malfunc- tions that may occur or all tests or inspections, and  corrective  actions.  If  a  malfunction  is  not listed    (except  when  malfunction  and  cause  are obvious),  or  is  not  corrected  by  listed  corrective actions  you  should  notify  higher  Ievel  mainte- nance b. Table 4-2 lists the common malfunction that you  may  find  during  the  operation  or  mainte- nance  of  the  generator  sets  or  their  components. You  should  perform  the  test/inpections  and  cor- rective actions in the order listed. NOTE Before  you use this  table, be sure you have per- formed all normal operational checks. If you have a malfunction which is not Iisted in this table, notify the next higher level of maintenance. Air  Force  Users  may  perform  maintenance  within the scope of their capabilities. Table  4-2.  Troubleshooting MALFUNCTION TEST OR INSPECTION CORRECTIVE  ACTION 1.   ENGINE   FAILS   TO   START   OR   MAL- FUNCTIONS Inspect  the  engine  for  electrical  or  mechanical  failure. refer to the appropriate service manual in Appendix  A. 2.   NO   OUTPUT   VOLTAGE   SHOWN   BY VOLTMETER Step 1 Inspect the voltmeter for signs of burning, broken or cracked glass, water or other dam- age.  Test  the  voltmeter  as  follows: Voltmeter (Ac Unit) a. Remove load cables from load terminals. b. Start the generator set. c. Position load switch to ON position. d. With a  multimeter  measure  the  output voltage  across  the  load  terminals  to  verify voltage on the set voltmeter should   not vary more than 9% Voltmeter (DC Unit) a. Remove load cables from load terminals. b.  Start  the  generator  set. 4-12 Change 8