Fuel difference

[Nickair]

Was your generator running? It comes of one the 2 tanks

1) Genset fuel draw
2) Filter restrictions
3) Fuel Vent/line restrictions
4) Fuel return line restriction
5) Operating torque or RPM discrepancy
6) Prop discrepancy
7) Heater System (Diesel)
8) Fuel leak
9) Fuel theft
10) Restricted crossover line
11) Fuel Manifold settings/restriction
12) Non matched injectors.

 

[High Wire]

How do you measure the fuel tank levels? Electric gauge, sight tube, stick, Hart systems gauge, other?

How do you know when they are full on your boat?


Agree completely with others to check RPMs at cruise with a photo tach. The typical alternator driven tachs indicated vs actual RPMs can be way off, then bringing them up even throws the engines out of balance.


How do you synchronize your engines if you do?

 

[mvweebles]

My fuel rate is different between the two engines the port using about 4.5 gph and star about 3.5 gph. I have been running the port at 1800 and star at 1900 . Last fill up was star 37 gal port 54 gal .. we also ran the generator fir about 4 hrs so that may have been the reason fir the port bring higher .. I had to have. It’s transmission oil coolers changed as be failed and filled the Transmission with sea water .. was flushed a few times seems ok now .. water pump Aldo failed and was replaced on port engine ...

That is a big difference. Gen might be 1gph (unless you have a 20kw or something).

I don't have any ah-ha ideas, but when engine off/gear in neutral, CA. You turn both props by hand?

Has this same trend been repeated in additional fill-ups? Just seems odd that only symptom is change in consumption - no new noises, no new operating characteristics, no odd heat rises, etc.

 

[mvweebles]

Also, any difference in exhaust? Smoke on one side?

My fuel rate is different between the two engines the port using about 4.5 gph and star about 3.5 gph. I have been running the port at 1800 and star at 1900 . Last fill up was star 37 gal port 54 gal .. we also ran the generator fir about 4 hrs so that may have been the reason fir the port bring higher .. I had to have. It’s transmission oil coolers changed as be failed and filled the Transmission with sea water .. was flushed a few times seems ok now .. water pump Aldo failed and was replaced on port engine ...

 

[KEVMAR]

Smoke is on both sides

 

[KEVMAR]

I know they are full because it comes out of the vent . Which has a side attachment that prevents the fuel from going into the water . I can also measure the amount of fuel with a dip stick on each engine

 

[EngNate]

Not considering changes or the accuracy of past and current observations, etc, but keep in mind that the side with the counter-rotating gear will use a little more fuel than the normal rotation side. This will be so with every counter rotating installation, except in the case of a counter rotating engine.

 

[mvweebles]

One side uses 38% more fuel than the other. Somethings going on but for the life of me, without other symptoms, I haven't a clue. Apologies to the OP, but that's why everyone keeps coming back to some flavor of mis-reading or poor reporting of consumption. Sounds like you've ruled that out. Please keep us posted.

 

[Ski in NC]

Get boat up to cruising speed/rpm. Phototach both the crankshafts and propshafts. Not much more to say on this until that is done.

 

[Mischief Managed]

My starboard CAT 3208 was using a lot more fuel than my port 3208. It was a bad injector that caused it. Only smoked a little more than the port engine when on plane. Otherwise, no difference in exhaust.