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...