Perkins 4107

[Capt Doug]

Fairly new to me boat never paid much attention to fuel consumption did a long trip an the fuel was over one and a half gallons an hour at just 1800 rpms

[Pandor]

Check for a dirty prop and bottom.

[Kettlewell]

That's pretty high fuel consumption for a 32-footer. What speed are you getting at 1800? Also, you need to do several runs where you fill to the top and then refill to get a reasonably accurate measure.