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John White
John White, Marine Mechanic
Category: Boat
Satisfied Customers: 306
Experience:  11 years experience working on outboards, inboards, sterndrives & pwcs
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My fuel management gauge is not reading properly. I am running

Resolved Question:

My fuel management gauge is not reading properly. I am running twin yamaha 200 hpdi engines. The engines and the gauge are new in 2007. Since that time and up until three months ago the fuel management gauge was accurate to within a few gallons. Now, the gauge consistently reads below the actual usage (i have tested it on five separate occasions). The formula is exactly the same where it reads 2/3 the amount of that i actually consumed. I realize there could be several explanations for this (and possibly others i have overlooked):

1: the sending unit on one of the engines is not working properly; (but then it would read 1/2 of what it should, right)
2: there is air getting in the fuel line causing the sending unit not to work properly; (i checked all the connections)
3: the fuel management gauge itself is not working properly and needs to be adjusted;

The fuel management gauge needing adjustment is the easiest and simplest explanation but I do not know how to adjust
Submitted: 7 years ago.
Category: Boat
Expert:  John White replied 7 years ago.
Are you using the Yamaha command link gauge or another manufacturer's brand gauge? I would assume the Yamaha gauge, but just want to check and make sure.
Customer: replied 7 years ago.
Yes it is the yamaha gauge... I looked behind but did not see any obvious spot to make an adjustment.
Expert:  John White replied 6 years ago.

The gauge can be calibrated within -7% to +7%, but that may or may not be your problem. You can also set the fuel sensor type in the tank as well as tank capacity. You can download the manual for your gauge at one of the following links. It will give you instructions for setting the tank capacity, fuel sensor type and calibrating the gauge if needed. All of this should be checked for accuracy & you should start off with the calibration setting at 0%. After running the engines you can reset the calibration setting as needed.


Square Gauge -

Round Gauge -


You can also use the gauge to look at individual engine information. With the ignition switch on press the "set" button to switch between information between each engine. Assuming you run both engines equally, both engines should show about the same fuel consumption. If one is a lot less than the other the fuel flow sensor on that engine is likely bad.


Testing each fuel flow sensor can be done without actually running the boat. Start by resetting the gauge to zero. Check one sensor at a time by disconnected the fuel line on the "out" side of the sensor. Connect a spare piece of fuel line and put the end in some kind of measuring container. Turn the ignition switch on and put the fuel flow display to that engine only. Next use the primer bulb to pump a measured amount of fuel through the sensor & then compare to what the gauge actually reads.

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