Fuel sending unit and fuel gauge issue.....

[bgreene]

Reads between 1/4 - 1/2 full but WRONG because I only had 5 gallons of fuel remaining in the 60 gallon tank ( it filled 55 gallons at pump )

I suppose i need to bend the float arm up a bit, but how much ?
Any ideas ?

1996 Wellcraft V21 specs indicate 60 gallon tank, not the 70 gallons some suggest.
So assuming the spec of 60 is correct, when I have less than 10% fuel remaining, gauge should read less than 1/4 tank .

[phatdaddy]

gas guages on boats are not very dependable. u could take your old one out, run it up and down and see if the needle reacts accordingly. i didn't have a gauge for 20 years. figure your mpg and set your trip odometer on your gps. with the old merc, i got 2 mpg, so i had a 120 mile range. the new motor has a smart guage that computes fuel useage and subtracts from the size of your tank and gives your fuel remaining as a %. i still set my gps and keep track of mpg.

[bgreene]

Ok, thanks

[tsubaki]

I would simply remove all the fuel, remove the sending unit, clean and inspect the bottom of the tank, replace the sending unit with a new one (making sure the float bottoms out correctly), with the tank level (manipulate the winch stand till so) start making notes at "E" and start adding fuel in 5 gallon increments and noting the locations on the gauge.

I've had two people complain to me about their boat getting good gas hours when they fill it up but then once they reach 1/2 tank the motor just eats up the remaining fuel quickly.

The belly tanks are not usually the same dimension/volume per inch of height therefore you would not expect the gauge to read correctly as to the actual fuel volume.

[tsubaki]

It has probably already been invented, so I won't ask for credit on it. A fuel gauge that can be calibrated at the 1/4, 1/2 and 3/4 marks.
Even MJ could calibrate it!
Picking on the 60 gallon fuel size just add fuel in 15 gallon increments and set the mark accordingly.
Or even one with a removable/replaceable face plate already calibrated for the differing tanks shape.

[Blue_Runner]

I just replaced mine. There was a calculation on the package. Also had the benefit of holding the new next to the old unit to compare. Old unit still worked perfectly but the design of top round piece (where the screws go) was terrible and allowed fuel to leak around the screw threads.

Mine was a Moeller.

[bradford]

Haven't run a fuel gauge in several years. A mechanical in tank gauge is on my to do list though, no wires, KISS.

[SkunkBoat]

60 gal tank but you will never get 60 into it before the vent spits. And that varies depending on how the boat is sitting. If you're in the water, it really varies...
also, don't bend it, you need to move the arm pivot point up or down and or adjust the length of the arm.
Bending will just make it wrong the other way.

If you read 1/4 when you are near empty, your pivot point is too low,or the arm is too long, or you need to turn the unit so the float arm orients along the centerline of the tank.
(i.e. its hitting the side of the tank)

tsubaki got it right, the v in the belly tank makes it impossible to be accurate thru the full range of the gauge. Watching it as you fill from empty is the ticket...
Of course, once you launch the boat it changes and varies by load.
They can make a calibrated one but $$$$$

I can put about 5 gal in mine after it pegs on full...just not worth messing with it.

[macojoe]

I am like spare, 20 years never had a working gauge, never ran out of fuel! just figure out what you use per trip and you should be good, I always fill up at the end of the day so i am always going out on a full tank!

[Blue_Runner]

Skunk, I pumped my 60 gal tank last year due to suspected trash in tank. When I filled I got over 64 gallons in it. Probably not 64 "useable" gallons, but 64 nonetheless.