Thanks for prompt reply. First of all some clarifications: (a) This problem of not starting happened all of a suddent without any warning. (b) When I drove the car, it kept running with just few ounces of fuel which I added in the air intake when I started the engine. It means that fuel supply must have started coming from the main tank otherwise, the car can not keep on running more than 45 minutes till I turned it off. Correct?

I will certainly check the fuel filter. The reason I did not check yet because when I drove the car, I did not sense any hesitation or symptoms of clogging. Do you agree?

I swapped the fuel replay from another 300E running car, but no change.

Do you think distributor rotor/cap can give similar problem? Again, if this is the problem, then engine should not even start- when I add fuel in the air intake.