TM  10-3930-638-24&P 12-9.   ENGINE   TROUBLESHOOTING   (cont) MALFUNCTION TEST  OR  INSPECTION CORRECTIVE  ACTION 5.  ENGINE  STALLS  FREQUENTLY  OR  DOES  NOT  DEVELOP  FULL  POWER  (cont) Step  7. Disconnect fuel line at fuel filter head. Place ignition switch in ON position and check if a slight buzz can be heard at electric fuel pump and if fuel is pumped out of disconnected line. Step  8. Step  9. Step 10. a. If slight buzz indicating electric fuel pump operation is not heard,  disconnect  wire  at  terminal  on  electric fuel pump and check for +24 Vdc between wire and chassis ground. (1) If +24 Vdc is not obtained, troubleshoot electrical  system  (para  2-19). (2) If +24 Vdc is obtained, replace electric fuel pump (para 2-15b). b. If fuel is not pumped out of disconnected fuel line, remove lines and fittings between fuel tank and fuel filter  head  and  clean/replace  lines,  in-line  fuel  filter, and/or fuel strainer (para 2-1 5). c. If fuel is pumped out of line, reconnect line and proceed to step 8. Operate  engine  for  15  minutes  at  idle  speed. Carefully  and  slowly  remove  radiator  cap. Check coolant temperature using a thermometer; be sure thermometer does not touch any metal parts  of  radiator. Coolant temperature shall be between 175 to 200 degrees F. a. If coolant temperature is not between 175 to 200 degrees, remove and test thermostat (para 2-17d). b. If coolant temperature is between 175 to 200 degrees F, proceed to step 9 below. Check for correct adjustment of accelerator/throttle control (para 2-15i). a. If adjustment of accelerator/throttle control is not correct, adjust (para 2-15i). b. If accelerator/throttle control adjustment is okay, proceed to step 10 below. Remove drive belt from engine water pump (para 2-17f). Start  engine  and  operate  at  idle  speed  for  five  minutes  maximum. Check  if  engine  power  increases. If engine power increases, replace water pump assembly (para 2-17e) and reinstall drive belt on water  pump. 2-20