Props for Suzuki DF40s

[cbgale]

I have twin Suzuki DF 40 four strokes on CD-22. Currently it is propped with11-5/8 x 12, 3-blade Suzuki aluminum props. I only have 30 hours on the engines, and they both turn up to within 100-150 WOT RPM, so it seems to be propped about right. My mileage is less than the 4-5 mpg that most seem to get, and is closer to 3 mpg. With 3 adults, and full fuel aboard, 4400 rpm produces 14-16 knots. WOT results in 27-28 mph. Does anyone have other pitched 3 blade, or 4 blade props on DF40s? If 4 blade, what pitch and Diameter? Should mileage improve much with additional hours of break-in?