TM 10-3930-653-14&P Condition Probable cause Corrective action IMPROPER ENGINE IDLING Fuel system trouble Clogged or damaged carburetor jets Clean or replace Incorrect idle adjustment Adjust Clogged air cleaner. Replace element Damaged  manifold  gaskets or carburetor Replace gasket or insulator insulator Improper float level adjustment Adjust Low compression Previously mentioned VALVE  ADJUSTMENT Incorrect valve clearance Adjust Extremely low revolution Adjust ENGINE POWER BELOW NORMAL Low compression Previously mentioned Ignition system trouble Incorrect ignition timing Adjust Faulty spark plugs. Clean, adjust or replace plugs. Burnt distributor points Dress,  or  replace  points  Also  check condenser Fuel system trouble Malfunction of choke system Adjust Clogged fuel pipe or floating valve Clean Dirty or clogged fuel strainer Replace Fuel pump will not work properly Repair or replace Clogged carburetor jets Disassemble and clean Throttle valve does not open fully. Readjust Fuel pump out of adjustment Readjust Air intake system Clogged air cleaner. Replace element. trouble Air leak from manifold gasket or carburetor Replace gasket gasket Overheating Insufficient coolant. Replenish Loose fan belt. Adjust fan belt. Worn or loose fan belt. Replace Faulty thermostat. Replace. Faulty water pump. Replace Clogged or leaky radiator. Flush, repair or replace 4 - 4