Fuel Gauge fluctuation?

[Techtraveler]

I took my new to me 17' 2004 Sea Fox out this weekend. Everything went pretty well, except getting an accurate Fuel reading. I put in about 20 Gallons of gas before heading out, the fuel gauge read full. Went about 18 miles and noticed the gauge was reading 1/4. Of course when I throttled up the gauge was reading full again. So how do you get a good idea of your fuel reading. I do not know by burn rate. I have a 2005 90HP Merc 2 Stroke.

Thanks

 

[skydiveD30571]

Re: Fuel Gauge fluctuation?

Pretty much every boat deals with this. Fuel is sloshing around in the tank so the float is traveling up and down. The best way, learn your fuel remaining at different stages. Fill it full, use it, and keep a mental note of the gauge reading as you leave the water. Fill it full again and record how much it takes. Over time I learned that my gauge reads full for about half a tank, then the needle starts moving. By the time it says 1/4 tank, I only have a few gallons left.

Trial and experiment, you'll get it.

 

[haulnazz15]

Re: Fuel Gauge fluctuation?

I'd imagine you'd get around 4mpg or so if at cruising speed with that 90HP and a light 17' hull. There isn't much that can be done about the fuel gauges simply because they are trying to measure fuel that is sloshing around in all three axes. There are different fuel cell designs that can include baffles to limit the sloshing, and fuel measuring equipment that can "dampen" the variations to give you a reading that fluctuates less. However, those options aren't cheap and really aren't necessary for most boaters. If you want the cheapest way to accurately keep track of your fuel usage/burn, get a fuel flow meter/totalizer.

 

[dingbat]

Re: Fuel Gauge fluctuation?

The float on the end of a stick type sensors sux. For less than $40 you can buy a reed switch sensor that eliminates most, if not all the bouncing around.

My two senders (main and aux. tanks) are connected into the fuel management system for display on my chart plotter as well.

 

[crabby captain john]

Re: Fuel Gauge fluctuation?

Rarely look at the fuel gage~~~~ the Yamaha display (can be connected to electronics) show amount used from last fill up. It measures what the motor burns. So ~~~~~ 90 gallon tank,,, easy to subtract and have the best idea....

 

[airshot]

Re: Fuel Gauge fluctuation?

Also do your homework and learn how much fuel your boat uses. It is as simple as filling up, go on a cruise and keep track of your time, then when done fill it up again and see how fuel you used. A few times of this will give you a real good estimate of your usage and it will become a breeze to know how much you used. Also it is a good idea to keep your tank full anyway as it reduces the amount of condensation collecting inside which is already a problem because it is a BOAT. I watch my GPS for time and distance and can tell usually within a gallon how much fuel I used each outing. I trailer my boat and can check the gage when sitting on the trailer which gives a more accurate reading anyway. Hope you find these suggestions helpful.