1988 420 fuel leak

[884201972]

Just purchased '88 420sel that has had minimal use for last 2 years. Only with car running, it leaks fuel from fuel pump area. Appears to be coming from top of fuel filter area and dripping on ground. Does this sound like the fuel delivery hose from tank? With car off, no more leak. Also note that it does not appear to leak with low fuel in tank. Am baffled at this point. Thanks, Steve