DK Diver
Cadet
- Joined
- Dec 18, 2019
- Messages
- 15
2008 Mercruiser 6.2 377 Mag. #1a314659. Fuel economy dropped from 2.5 MPG to 1.8 MPG, instantly while up top and running 3600 RPM. The power loss felt about the same as trimming the motor back down, and the engine sounded like it loaded up a bit. New fuel filters, new plugs, new plugwires, new cap and rotor since the issue. On the next outting, low fuel economy, but it jumped back up to 2.5GPM for a few miles, then back down. You can hear and feel the difference when it happens. There isn't any popping, sputtering or anything like that, it actually runs decent but a normal 40 gallon trip is a 50+ gallon trip. No alarms. 2 fuel tanks, same result on each tank. WOT for 3 minutes @ 5100 RPM's, no fluctuation. Fuel pressure is 39 PSI @ idle. 165 degrees engine temp on the dash. I have spent some time reading the forums, tried to find as much info as I could.