The US cars had a fuel return line to the tank and a vapor vent to a cannister in the trunk. Does your car have these?

I agree that this is a fuel problem. The Zenith's are famous for allowing fuel to evaporate and if any component in the fuel system is faulty, it can take a while cranking for them to fill back up enough the get fuel through the venturi and accelerator pump. But if it takes a minute of cranking, then you have a problem with fuel flow.

There is a strainer in the tank and small filters in each carb's inlet. Depending on the style of your pump. you may have a small brass filter on the inlet, or a larger cone filter under the cover. If any of these are plugged, you could have a fuel flow problem. Your pump may also be weak.

You can test this (except for the carb filters) by pulling the coil wire, disconnecting the fuel line at the carbs and sticking into a container, and having someone crank the engine while you watch. I have never seen a spec, but the Haynes manual says "well defined spurts" should be observed.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe