My cat has a pair of D2-55F Volvo
diesels. Port is original 2009 with about 2,810 hours, Starboard is newer 2014 with about 990 hours. Each side is a standalone system with its own fuel tank
and return line to that tank.
We frequently run one engine
at a time, and if I need to charge of course run just one. I've been running the engines mostly by the fuel
gauges - keeping an equal amount of fuel
on each side. I know the gauges are basically correct, because we've been putting an equal amount of fuel into each tank when we refuel.
Now 10 months later, on essentially equal amounts of fuel (give or take 5-10 gallons AT MOST), the port engine
has run 230 hours and the starboard engine has run 200 hours.
As a broad average we burn about 1 gallon an hour across idling, motoring, charging
, etc., etc. So starboard is consistently burning roughly 10% more fuel.
Exhausts looks identical - no sign of a dribbling injector or other similar. The engines behave identically at power - same RPM
gives same boat
So - ideas???