This is not a direct answer to the question but most of the time run our Honda 2.3 at just enough rpm to fully engage the centrifugal clutch. On flat water this results in 3.5 to 4 miles an hour (less in knots of course). We pump our tank full from an external tank and a full liter-or-so tank lasts 2 hours or more at this throttle setting. David Grah1986 Montgomery 15Sky Date: Thu, 21 Mar 2024 05:56:44 +0000 From: Jim Sadler <jimsadler@jascopacific.com> Subject: M_Boats: 2 hp Honda runtime To: For and about Montgomery Sailboats <montgomery_boats@mailman.xmission.com> Message-ID: <BY5PR13MB38594FEF76687EC256BE3A1DD5322@BY5PR13MB3859.nam prd13.prod.outlook.com> Content-Type: text/plain; charset="us-ascii" Good Evening Skippers On M15 at 4 knots how much run time do you get per tank of gas? Thanks Captain Jim SV Pelican