Ryobi / MTD cultivator 410r has the same engine as the newer model Ryobi 21A-121R034. Look on the web for Super X Power Center, 170 Central Avenue S. Milaca, MN 56353. They list this part as #791-683974 Primer & Hose for $17.31 Have fun gardening.
Tractorman 623
June 2008
Go to Home Depot and find a similar one on a newer Ryobi tool.
Get the part number etc, and order that. I found one on a gas Ryobi blower that fit my 10yr old Homelite gas trimmer. It was identical. So I got the part info for that Ryobi and ordered it, as I could not find a primer bulb for the old Homelite. Good luck.