220d hard starting

I have a '69 220d auto. It has over 330k on the od. I have little history on it but it still runs with some effort. When it's cold I have to pump the gas peddle as I crank over the engine and once it starts I have to keep the revs up for a few minutes until it goes into a rough idle. This car is far from being a nice ride but I got the car basically free. Any ideas on my problem? Thanks Courtland Also, how hard is it to convert to biodiesel and how easy is it to put a bigger diesel engine in it ? The 240d comes to mind. I also have trans. problems but I'll save that for another day. Thanks again