Window will not stay open

Hello, thank you for posting,

At first sight, it appears your window uses the 15-199 pivot shoe, but to further review, we will need to see the window sash removed for a clearer view.

It would be best to see the assembly removed from the window as we will also need to know if the original coil springs measure a 1/2" or 3/8" thick to move forward along with any numbers stamped on the springs. From there we can confirm the correct series for your window. Thank you!