Doug Brooke at Vintage Outboard has the left hand thread prop nut.
http://www.vintageoutboard.com
On the home page, scroll down to “Parts Other Brands”.
You can put an ad in the Classified section here for the prop.
Bob
1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1957 Evinrude 3022
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20
“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."