Fuel Gauge

[tsubaki]

Normally it is only possible to make adjustments on the sending unit and not the gauge.
Depending on the type of sending unit you have, you can do the adjustments that you are describing.
If the sending unit is the stem type, usually the only adjustments possible would be for the tank depth.
The usual sending units of the arm type can be manipulated some in order to reflect a know level (as in your case) by bending the arm at some point between the float and the sender itself.
Bending the arm to make the float deeper would adjust the sender toward a more "full tank".
In your situation, it is probable in doing this, the arm may contact the top of the tank when not quite full of fuel.
If it were me, I'd have to find the actual tank size, even go to the point of draining it, refilling it to full, then remove 1/2 of the fuel and then do the adjustments to the sender or the manual portion, whichever is incorrect.
Again, this is making sure the tank is level.

[Bygracealone]

Originally Posted by tsubaki

Normally it is only possible to make adjustments on the sending unit and not the gauge.
Depending on the type of sending unit you have, you can do the adjustments that you are describing.
If the sending unit is the stem type, usually the only adjustments possible would be for the tank depth.
The usual sending units of the arm type can be manipulated some in order to reflect a know level (as in your case) by bending the arm at some point between the float and the sender itself.
Bending the arm to make the float deeper would adjust the sender toward a more "full tank".
In your situation, it is probable in doing this, the arm may contact the top of the tank when not quite full of fuel.
If it were me, I'd have to find the actual tank size, even go to the point of draining it, refilling it to full, then remove 1/2 of the fuel and then do the adjustments to the sender or the manual portion, whichever is incorrect.
Again, this is making sure the tank is level.

Thanks T. I'm going to try to contact the previous owner and see if he can recall what size tank he put in it. I'll let you guys know what I find.

Your help is much appreciated.

[macojoe]

i have a 110 gal tank i use 25 gal most trips and fill after every trip, so i no give a crap about the gauge!!
this boat the Sea Ox longest trip was 80 miles round trip, and used just 30 gal

[Bygracealone]

Originally Posted by macojoe

i have a 110 gal tank i use 25 gal most trips and fill after every trip, so i no give a crap about the gauge!!
this boat the Sea Ox longest trip was 80 miles round trip, and used just 30 gal

I might follow your lead there MJ!

[Cam]

Can you actually get a measuement of the tank. There is a formula for figuring out gallonage in a tank.

Tank ( Gallon Volume ) Formula

( L x W x H ) / 231= total gallon volume

ex: 14”x14”x72”…..

14 x 14 = 196

196 x 72 = 14,112

14,112 / 231 = 61.09

61.09 total gallons

1 cubic ft = 7.48 gallons

[Bygracealone]

Originally Posted by Cam

Can you actually get a measuement of the tank. There is a formula for figuring out gallonage in a tank.

Tank ( Gallon Volume ) Formula

( L x W x H ) / 231= total gallon volume
ex: 14”x14”x72”…..
14 x 14 = 196
196 x 72 = 14,112
14,112 / 231 = 61.09
61.09 total gallons
1 cubic ft = 7.48 gallons

Thanks for this Cam. I might be able to find the dimensions on the paperwork that he passed on to me when he purchased the tank...

[garbubba]

Maybe I missed it, but is your tank guage a mechanical one? The trick would be to figure out which guage is correct (if either) it's pretty easy to make some adjustment by just bending the float arm on the sending unit.
Otherwise do some math & figure out what it really indicates & just compensate.

I used to have a mechanical & an electrical guage & I still ran out of gas 'cause I trusted them too much, they were both broken!

Now I make sure I have plenty & I top off the tank to make sure.

Doug

[SkunkBoat]

Doesn't matter how much the tank holds, just the depth of the tank.

Can't you just remove the sending unit with wire still connected
(You need to connect a jumper to ground to get a complete circuit)
, measure the depth of the tank with a ruler, check the swing of the float to see where it gives a full and empty reading, adjust the length of the float arm so that the range corresponds to the tank depth, put it back together?


Sending unit reading is linear. Square/rectangular tank volumes will read correctly.
If its a belly tank it will not be linear because there is more volume in the top half of the tank than in the bottom.