This bearing is also known as:
FAFNIR: P204RR6, 204KRNP-2 
BCA: 204BBAR
Link-Belt: SC0451IIC3
NTN:

APPLICATION:
Allis-Chalmers #536986
Ariens #54120
Bolens #1185828
John Deere #JD9296
Rotary #09-484
Simplicity #108202
Snapper 13313
Yazoo #204-060
Lilliston: 20-50-094
Swapper: 10696
IHC: 465003R91

DIMENSIONS:
BORE: .75" Round
O.D. 1.78" Flat
IR Width: .61"
OR Width: .61"

Used on various cultivators, gauge wheels, planters, disc tillers, mowers, spindles, lawnmowers and other implement applications.