Does my diesel have a fuel water separator?

I just purchased my second MB. A pristine 1980 300D. Everything is great other than a shudder form the engine when it starts in the morning or after sitting a few hours. I had the valves adjusted and it still shudders until the temp goes to 40 C. I noticed under the hood on the drivers side a canister with a drain on the bottom, a filter inside, and a air valve on top. It has two fuel hoses that have been cut leaving it unattached. Did this come with my car originally, or is it an add on? My service manual doesn't mention it. Could this be the cause of my shudder?

thanks again,
jmdunn