Cruising speeds

[Chilly willy]

whats the best speed or rpms for gas mileage on an 2575 with a 250 verado pro?

 

[Michiman]

According to my gauges, my sweet spot is about 3700 RPM or just over 20MPH with about 2.9 to 3.0 MPG.

 

[Link]

Don't see performance bulletins for Mercury but here is one on a Yamaha VF250XA V MAX SHO on a 2275 RCW. Looks like 3000rpm is the sweet spot.
https://yamahaoutboards.com/en-us/h...l/vf250/pb_bnt_2275rcw_vf250la_2012-05-14_pnt