I don't believe there's a screen in the Stromberg carb. Usually those Mercedes used a screen in the tank and another under the fuel-pump cover. I like to install a proper in-line fuel filter between the tank fuel-line under the battery, and the pump.

Between 1971 and 1973, Volvos used twin Strombergs on most of their US-market cars. Unfortunately, if you're looking for a possible parts-source, I don't believe those had fuel cut-off solenoids. Starting about 1974, all US-market Volvos were fuel-injected.

Happy Motoring, Mark

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DrDKW