Suzuki DF20ATL2 Prop Selection

[mje131]

I have a 2019 Suzuki DF20ATL2. Original prop is an aluminum 3 blade 9.25in 9 pitch and it works well on my 16ft 1979 Bass Tracker. I purchased a Solas stainless steel 9.25in 9 pitch as a replacement. The stainless steel doesn't work properly. RPMs seem to max out/over rev but doesn't push boat to max speed (half the speed of the aluminum). Do I need to increase or decrease the pitch if I want to change to a stainles? Or should I just stay with aluminum since a small engine?