fuel burn

Hi All, Twin ‘98 7.4 454 Horizon Engines looking for some general suggestions on what to check as my port rpms are jumping around a good bit. Not at idle but at running speed up to 400 rpms up and down. Starboard maybe 100 rpm fluctuations. Not sure if injectors are all original or not but...

Just recently took delivery of a 2017 400 fly and looking for feedback on performance: Twin Cummins 6.7 QSBs @2700 RPM 80% load 38 GPH Speed 18.2 knots Props just refinished. Seems slow and fuel burn seems high. Specs from boat test of same boat have her at least 23 knots and lower GPH...

I just installed a terrific Garmin chart plotter and GFS10 fueld monitors on my twin 4.3 IOs. The last step is to hook up the fuel tank. I need the ignition switch and the fuel level. I pulled the gauge and have 4 wires. Does anyone know which two I need? Thanks, Mark

Hi, I'm looking at a 1991 Sundancer 270 with a 7.4 BB and Alpha One drive. What rpm would produce the best fuel economy? thanks rory