Hello BB and welcome to the Grumble,
Hopefully I might be able to offer some assistance.
"naturally swivel on the bar"....means rocking left and right on either side of the bar that runs down the middle of the clamp?
If this is the case, then you need to adjust the small allen screw that sits inside the right side of the cutting head. While the head is in motion, if you turn this clockwise, it will put force on a small bearing that runs on the right wear strip. This should eliminate play in the cutting head over the bar.
The two other openings (allen screws) on either end of the cutting head adjust the two bushings on either end. They in turn, eliminate play on to the head left and right as a side to side motion.
Did you take the head off the clamp to assure that the bearing is still in place (right internal). The first models had only two bearings while most F-2000's had three.
The F-2000 was introduced in 1987 and replaced by the F-2100 in about 1991-92, but you might still be able to get your hands on an old manual if you don't have one.
Get back to me if I can be of further assistance, or contact customer service at 1-800-THE-FTCO.
Regards,
John