what rpm is the best mpg on a 175 1990? is WOT rpm 5k o.k

[alex3012red]

I just got a trophy 21 ft cc 3350 lbs, with a yamaha 175 1990 on it. what kind
of mpg should i be getting. wot it does 45mph at 4800 to 5000 rpm. 3k rpm 25mph, 3.5k does 30, 4k does 35, 4.5k does 40, but i have no idea on what mpg iam getting. thanks for any info.

[tunnels]

General rule of thumb was keep the cruise rpms below 4 k and that would be the most economical range .
Depends how the hull is set up along with the trim etc .
There are gauges that will give you the info for what you are looking for !
Also some gps units have a plug in fuel flow sender and the soft ware already built in .

[alex3012red]

thanks for the info, for now I will keep it under 4K.