Author Topic: Deluxe fuel system (and how to know exactly how much fuel is in your tank!)  (Read 1806 times)


  • Newbie
  • *
  • Posts: 15
    • View Profile
Want to easily determine the amount of fuel in your tank?
Weigh it!  (See photos, below). 

This method has three big advantages:
(1) it does not requier installing a gauge in the tank;
(2) the shape of the tank does not matter;
(3) it always gives temperature-corrected gallons.

The diesel fuel storage and gauging system describe here isn't
application-specific, but happens to be on a SR-1 Kohler genrator.   
I'm guess it may interest other generator users, since having the
lights go out unexpectedly is a pain.

Most of the parts (fuel line, fuel filter, etc.) are large enough to accomodate
the fuel flow requiementsof any Lister engine, but you have a larger engine,
you might need a larger  fuel tank, depending on your particular situation.


fuel_volume = (measured_weight - tare_weight) / K


fuel_volume is the amount of fuel left in the tank
measured_weight is the reading on your scale
tare_weight is the  weight of the tank when the engine
    runs out of fuel and starts sucking air.
K is a constant that depends on the units of measure.

USA example:

standard_gals = (measured_lbs - tare_weight) / 7.1

Diesel #2 fuel weighs 7.1089 lbs per standard US gallon.
("Standard gallon" means volume measured at 59.0 degrees F.
As diesel fuel warms up, it expands.)

Metric example:

standard_liters = (measured_kg - tare_kg) / 0.8598

because Diesel #2 fuel weighs 0.8598 kg per standard liter.


1 crane scale   
ModernStep digital crane scale, 300kg/600 lbs (made in China). 
Not great, but adequate.   Runs on three AAA batteries.

1 scale cover   
Zip-lock storage bag (to make scale more weather resistant)

1 tank             
15-gal stainless steel barrel drum, closed top

1 filler, cap and vent          
Assembled from galvinized pipe parts. Internal vent  and screen
added to filler.   External vent U-tube added to pipe cap.

1 tank lifting bracket   
fabricated (parts used to be the towing hitch for a '58 Porche
Speedster back in the day)

1 bung adapter   f
For fuel dip tube and fuel return line. NPT thread.

15 ft fuel line          
3/8" nylon air break line (meets DOT requirements)
with compression fittings

1 primer bulb   
Attwood universal 3/8" (WalMart)

1 course fuel filter   
Dutten-Lainson "Goldenrod" 496 with 496-5 water-block element.
Also removes paricles down to 10 microns.
Modified to add air bleeder valves on inlet and outlet. sides.

1 fuel lift pump   (not shown)
Carter P4070 universal in-line 12 VDC rotary fuel pump.
Sliding vane type.

1 fine fuel filter (not shown)
Kohler/Lister original part  on engine


The arm the crane scale is anchored to is an extension that fits into the
square stock inside the generator shark.  (The square stock has a sliding
anchor for the chain hoist used to lift the generator when necessary.)

After having a lot of problems with steel barrels rusting out, I went to
a stainless steel tank.   Copper fuel lines were causing black sediment,
so I went to nylon air break line instead.
I did not purchase a larger tank in order to insure that fuel would not
be stored for long periods (because of the problem of microbes growing
in diesel fuel).

I wish the tank had a drain to remove water, but adding one is not worth the
risk of creating a leak.  So I siphon the tank bottom about once a year.

I chose the Goldenrod filter because I can buy replacement elements locally,
and because I wanted a filter with a transparent bowl (with a drain).
It's designed for dispenser use and so is massive overkill for an engine.
Also, a filter that comes with bleeder vales would be better. 

The Lister built-in lift pump died years ago; then a series of electric diaphram
pumps died---none lasted longer than six months.

I wouldn't recommend switching to an electric fuel lift pump, because it
adds quite abit of complexity and new points-of-failure.   But if you do,
a rotary pump will last much longer than a diaphram pump. Also, diaphram
pumps made for diesel fuel aren't cheap--so you might as well spend the
money on a good rotary pump.


  • Mendocino Metro
  • Hero Member
  • *****
  • Posts: 1527
  • Mmmm BBQ
    • View Profile
    • Mikes Solar PV page
I use a length of clear tubing, marked in 1 qt intervals, from a T at the tank outlet, to a matching T in the diesel return line at the top of the tank. 
I'm using the listeroid tank, set on a shelf, and refill from 5 gal cans.


  • Newbie
  • *
  • Posts: 15
    • View Profile
That's a great idea to have a tee to the return line, Mike,
I suppose you had to fill the tank one quart at a time in order
to calibrate the gauge.

I like sight tubes--I just wasn't sure what clear, rigid material
to use.  Or how to build one that wouldn't leak.  I didn't think
of using two tees.

I had a short section of clear vinyl installed as a sight tube
at the pump inlet for a while, to watch for bubbles..  But it leaked,
so I removed it. Probably I used the wrong barb fittings.

I find dipsticks can be hard to read in dim light.  Sometimes I even
have trouble reading the Lister dipstick after an oil change.
Over the years, the matte finish on has erroded at the oil line. (Wish I
knew how they created that finish on steel: sandblasting?   Chemical
etching?   I'd like to renew it, since I can't buy a new dipstick.)

Delo Super 1300 contains something (a dye?) that fluoresces weakly
in UV light.  I used a UV LED light for a while but it didn't help much
and was a lot of bother.

But the worst problem is that when I pour the motor oil into the filler
on the head cover, it takes a while to percolate down to the crankcase.
So It's easy to overfill the engine.

I finally added a quick drain on the crankcase, so small overfills can
be corrected easily.


  • Hero Member
  • *****
  • Posts: 653
    • View Profile
Hold a small torch behind / alongside the sightglass and move it up and down.

Even with a very grubby 'glass' it's usually possible to see the level, due to the way the light changes as it passes  through liquid, and then through air.

Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.


  • Jr. Member
  • **
  • Posts: 69
    • View Profile
A pressure gauge could be simpler?


  • Casey
  • Hero Member
  • *****
  • Posts: 2127
  • What? My diesel had fries for lunch?
    • View Profile
I can almost always find a stick on the ground and use it as a dip stick.  Of course if I have to spit on it to clean it up I can't use it till the next day - QC requirements.
NPR Tipper/Dump Truck
Kubota BX 2230
Witte BD Generator
SunnyBoy 6000 + SolarWorld 245


  • Full Member
  • ***
  • Posts: 116
    • View Profile
There are many roads to Rome, but I like this one. I've been busy with arduino and a acoustic distance sensor but never finished it.

Looks neat.