Twin Perkins 130 HP, 6.354M. When I bought the boat new, the dealer stated that at cruise speed, 2400 rpm 10 knots, was between 6 and 7 gph. Faster than that, up to 2800 rpms I'm sure it goes up dramatically. I carry 500 gallons, provides plenty of range for cruising the coast up to SE Alaska.
I've never bothered to confirm that info as fuel was a very small part of the expense of owning the boat and we spend so much time idling and fishing, it would be hard to determine anyway.
Good luck in your search.
Careful . . .I Have a Generator and I'm not afraid to use it !