Ford Repair: Dieseling after shut off Engine, coolant fluid, dieseling

Question
hello, i have 1981 F-100 with the inline 6 Cylinder ( 300 ) 4.9 Liter , I changed plugs , Wires, Cap,Rotor, Air-filter , timing adjusted, it runs good , but when is warmed up ( after 20-30 KM ) and i want turn engine off is still running 0 dieseling ! what could be the Problem , also changed Thermostat and coolant Fluid
Thank you in advance .....  Uwe

Answer
Uwe, If you are positive that your timing is properly adjusted and your chain is not old and need replacing, then I would suggest that you rebuild your carburetor, or buy a new one.  "Dieseling" is usually caused by an engine getting out of time.  After your engine warms up, the chain might be stretching just enough to throw it out of time.  A carburetor can also cause the engine to try and turn over by pouring more air and gas into the intake after shut-off.  I hope this helps,   Jason