2800scr gas gauge?

[George K]

Hello,
Got a question to you learned Maxum veterans. On plane my gas gas seems to read more accurately than sitting at the slip (which happens to read lower fuel).
Did the Maxum engineers, decide to calibrate the fuel gauge to running on plane?
Seems to make sense to me.
Anyone out there with similar observations? Or... am I just having issues with my sending unit?

[shrew]

My 1997 2800 was the same way. The fuel sender (Which is nothing more than a float) sits at the aft portion of the tank along with the fuel pickup(s). That makes access and servicing easier. I suspect the boat sits stern low and lift when it's up on plane. Certainly water in the bilge runs aft when sitting.

Whether that was intended, or "A happy accident", I'm not sure.

[George K]

Thanks shrew,
I think that the engineers intended the gas gauge to be read while underway - for practical reasons. I found that at my slip, the gauge read 1/4 when there is actually about 1/2 tank left. Thee float is therefore intentionally placed higher to compensate.

[jparsons121]

Gas gauges on most boats are highly inaccurate and are really only for relative or approximate guesstimates. Not like a car which people rely on to know how many miles until really empty.
You give the engineers way more credit than I do. Usually the sender is selected by the depth of the tank, where by default, float all the way down = Empty and all the way up is full. No calibration, etc. With the shape of the tanks in most boats, the number of gallons in the tank vary with the levels as well.
That’s also why most boating courses provide the 1/3 rule for fuel. 1/3 out, 1/3 back and 1/3 in reserve. I’m not referring to 1/3 of a tank, but the fuel needed to do a specific trip.
To accurately know what’s really in the tank, use your a log book. I log each trip and fuel up, so knowing my average burn rate, I can calculate gallons remaining after each run. My math should sync fairly closely with the gauge, but when in doubt, I go with my calculation, not the gauge.

[George K]

I do use the 1/3 rule. My chart plotter also calculates fuel burned - so between manual calculations, the plotter and gas gauge, I have a pretty good idea.
Unfortunately, the 2800scr has only a 100 gal gas tank - so determining range becomes critical for me. As opposed to most marina patrons that generally sit around at their slip at the marina, I like to travel around in my boat.
Thanks again for your advise - I like this forum.
George

[jparsons121]

I’m with you George. I have a 3000with dual tanks, so I need to factor in fuel stops or we aren’t getting very far.