__IGNORE ALL THIS IF YOU'RE USING A NuBus SCSI CARD__
The fact that you have 4 instead of 3 SCSI ID jumpers indicates that you have a 68-pin SCSI drive instead of an older 50-pin one. Older 50-pin SCSI only supports SCSI ID numbers up to seven. Your biggest problem is probably that jumper on SCSI ID bit 3.
The correct jumper settings will depend upon where the disk is installed in your Mac:
If it's internal, with no other hard disks, you probably want to remove all the jumpers, then put one jumper on the "TERM PWR" and one on the "SCSI TERM" line.
If it's external, set TERM PWR but not SCSI TERM. Then, set a SCSI ID that isn't already in use. Use a tool like SCSIProbe (copy it onto your disk tools floppy... it's small) to check which IDs you're already using.
Setting the SCSI ID is pretty simple with a little binary math; the SCSI ID signals 0 through 3 are for the bits of the SCSI ID number. The #3 jumper is worth 8, the #2 4, the #1 2 and the #0 jumper is worth 1. Add up the values of the jumpers that are in place to get the SCSI ID.
(example: jumpers on #1 and #2 == 2 + 4 = SCSI ID 6; no jumpers == SCSI ID 0 )