Fuel burn rate

Dirtythirty

Looking for ideas as to why my engine monitoring system is telling me that my port engine is burning more fuel than my starboard engine.  Both engines are running at the same RPM, trim tabs are in the same position on both sides.  The difference is not minimal...I'd say that if my starboard is burning 13.5 gph, the computer is telling me the port is burning somewhere close to 14.7 gph.  My drives are fixed and do not trim,  and as far as I know they are aligned properly.

Other than what the computer is telling me, the boat and engines are running fine with no issues.

Volvo D6 370hp X 2
IPS 500

Thanks for your thoughts

Handymans342

Did it just change?

Black_Diamond

My analog fuel flow meters always show one engine burning more than the other. Maybe ~1 gph. 

Dirtythirty

@Handymans342  there was always a small discrepancy....but I don’t recall it being 1mpg or slightly more.   Maybe I’m making a big deal out of nothing. I just never noticed it before .

Michael T

...... slight trim tab discrepancy despite what gauges are indicating, some barnacles or bottom growth more to port?

Dirtythirty

@Michael T   perhaps...I will find out in a week or so when I get hauled out !

Handymans342

I would think that any underwater fouling would be equal on both pods therefor slowing the whole boat using more fuel on both engines and not one more than the other.

Dirtythirty

I'm leaning more towards the idea that it may just be an electronic anomaly.  I can't figure out how the main computer would be able to determine exact fuel burn. and then electronically adjust the injectors so as to match both engines exactly.  Its way above my pay grade, so I may just have to live with it up until it becomes an issue. As I said. everything is working great.  

Handymans342

Did you ask a Volvo tech or call their Tech service?

Dirtythirty

@Handymans342 next on my list, figured I'd give you guys a try first

Handymans342

Sorry, we tried. 

Handymans342

Diconnect it and dont worry. 

zaverin1

Port always burns more
ccwr always burns more 

rasbury

Ccwr?

zaverin1

Counterclockwise reading

zaverin1

Most rinker are indentical when it comes to layout
bench aft
ans either straightl shaped seat on port
where everyone sits usually 
besides port using more fuel naturally it also has to work harder to keep the rpm synched

LaRea

If you have one engine consistently burning 10% more than the other, you would eventually have to add 10% more fuel to the tank on that side.  Do you always pump the same number of gallons on both sides?

Handymans342

I know I don't because of the genny

Dirtythirty

LaRea  to be honest...I have never paid attention to how much fuel I put in either tank.  I have a scientific way of figuring out how much fuel goes in...I insert the nozzle and begin pumping, it is at that point that I realize the amount of fuel going into my tank is exponentially at a lower rate than the amount of cash flowing out of my wallet . The latter of which is usually empty much sooner than the former in full. 

LaRea

Cruise until fuel tanks are empty.  Fill tanks until wallet is empty.  Repeat.

It's a mantra for the power boating lifestyle.

reneechris14

I always have trouble telling when the tanks are full I hear some gargle and stop. Always 5ish gallons different either side. Then the gauge says I could put more in. It's s good thing the beach is only 2.9 miles for the marina. Boat does not always go far.
Power comes from fuel 
Fuel comes from $$$

Wildboating

Are you running the generator when away from the dock?  I believe it pulls from the port side tank.   Depending where you are measuring from this may explain the difference  

Dirtythirty

@ Wildboating:  we have run the generators, but rarely while under way.  The last time we were out, then engine monitoring system was getting its figures just from the engines.  I am not sure, but I believe it gets its calculations from the digital fuel metering into the engines, and not from the amount of fuel in the tanks.  However, what I did find strange, is my fuel gauge has mysteriously stuck on "100%"   although I doubt the two are connected, its a strange coincidence.