Delta jointer serial number 2-1102

Hello: This is an old Delta jointer which I believe is from the late 1930's or early 40's. It was my grandfather's machine and it has served me well for many years. But now I am having a problem with it cutting tapers when face jointing. It is taking more material off of the leading edge than from the trailing edge. Also, there is less material being removed from the fence side of board when I draw a squiggly pencil line. I have set the knives several times with a jig in conjunction with a dial indicator so I'm quite sure that that is not the issue. I have checked the tables to make sure that they are coplaner. But when I run a dial indicator on the outfeed table from the fence side to the other side, the fence side is .002 higher. Could this be my issue? I don't know what else to check. If that is indeed the issue, I'm thinking that the outfeed table needs to be shimmed on the one side. I'm not sure on how to go about this on this machine. As you can see in the one photo, there are four screws on the pulley side on the base casting which I'm hoping has something to do with resolving this. I really don't see any other kind of adjustment. I would really appreciate any help that someone could give me. I really don't know where to go from here and until I get this machine back in service, I'm kinda at a standstill. Thank you for your help.