Tman
Member
- Aug 10, 2012
- 284
- Boat Info
- 2014 Sabre 48 Salon Express
- Engines
- Twin Cummins QSC 550
Zeus Pod Drives
I have a 2005 390 Dancer, twin Cummins QSB5.9, 21x23 props, 540 hours on the engines. I notice a fuel consumption difference between the engines at cruise (~2540 RPM's on each engine) of about 1GPH with the port engine drinking a bit more. The % load on the port engine is also running about 5% pts more than the starboard engine which would indicate to me it is working harder than the stbd engine to achieve the same RPM. I've had the boat for about a year, it was surveyed by a credible firm, and overall, she's in great condition and maintained the same. I also recently had the props reconditioned hoping that might level off the fuel consumption...but it didn't. Overall, my fuel consumption on the boat is on spec for the 390DA with these engines(~29GPH at cruise). Any ideas as to what is causing the difference? I've heard (but never validated) that since the props are counter rotating, one engine will consume a bit more fuel than the other due to fundamental gearing differences between the transmissions. Not sure I totally buy that. I've ruled out fuel consumption by the genny as the culprit. My last question is; what is excessive....is 1GPH "a bit" or "a lot"? Over a long haul, its a fair amount of fuel, although on refills, I'm adding very similar amounts to each tank. The fuel consumption does level off as RPM drops....at idle or trolling speed, they are exactly the same.