[graham7773]

Good to hear your car is running ok now. Yep, they (the corroded parts) are for "pollution control" today known as emission control as well. You probably will be at little risk of getting caught but if your emission control system is not working properly, there are some fairly heavy fines out there you can be hit with. As for a "non return valve" or one way valve in the fuel line I must have missed something in my experience with carburetted engines. Never seen one. Most of the earlier Japanese and Korean cars actually had a return to tank line which operated when the engine was on over run eg coasting down a hill with the mechanical fuel pump still pushing fuel to the carby. Excess fuel was diverted back to the tank through the fuel return line. Have you replaced your fuel tank filler cap recently? Vacuum build up in the tank can draw fuel back to the tank. The cap has a one way valve in it. If it fails you get either vacuum build up or pressurised tank.