Does anyone know what the burn rate is in the TAMD 40 B. When I bought my Marine Trader it had new fuel tanks but no gages. Until I install my Tank Tender system I don't have a clue to what I am burning.
How big is the boat, how heavy, and how fast are you going? That engine could burn from 1gph to 8gph depending on how hard you are working it. Which we do not know.
My 10,000 lb boat with a TAMD-41P (newer version) burns 2 GPH at cruise (2000 rpm's, 7.5 knots) FWIW...
Fill your tanks, run for 40-50 hours and tank up again for a good average for you.
My rate is measured over 4 years and 300 hours..
With your larger boat, I'd expect 3-5 GPH..
At a 2K rpm cruise they are pretty economical assuming you are propped correctly..