OK, I give up, so just how DOES the fuel
system work?
Don't feel bad, the fuel delivery system
and the gauge system is "unique" to the coach, thats saying it nicely.
Actually, the fuel system is weird and does not use proper logic, if you ask me.
Yes, there are 2 fuel tanks (25 gallons each), but no, you cannot use them
seperately. Both tanks are filled from a common fill line and are actually
tied together via the fuel fill rail on the side of the tank. Each tank
has a fuel liver sender and you can look at each tank using the fuel switch on
the dash
When the "main" tank is selected, you are looking at the rear furl tank sender,
the fuel travels from the rear tank through the selector valve and on to your
motor. You have availability through the main sender of all for the fuel
in the main (rear) tank as well as 3/4 of the fuel in the front tank--- how can
this be? The fuel mixes from both tanks via the fill rail located a the
1/4 level on the side of the tank. When the fuel level in both tanks reach
1/4 together (& they will reach it together), the tanks no longer share fuel and
your fuel gauge will drop like a rock in that it will then only pull from the
rear tank. Flipping the dash switch to "aux." switches the feed to the
front tank where you will then have access to the 1/4 tank (@ 6 gallons) trapped
below the 1/4 level common fill rail. So in reality, the system acts just
like a "reserve" position on a motor cycle pet cock valve. When the fuel
gauge on main shows empty, you should have @ 6 gallons in the "aux." tank when
you flip to the aux. switch position.
OK, now that you see this, you can
understand that having 2 senders is a bit redundant in that they will both read
the same until you reach the 1/4 full mark. So you say, whats the beef,
who cares-- well you won't care as long as you know what the gauge is telling
you until you have a bad sender and look to replace it.
The senders are $125 each, a small price for such a special part but wait--- do
you really need to spend $250 when renewing your fuel system? No, you can
replace only one and still be able to reliably read your fuel level and here is
how.
The main tank is the rear tank, OK, lets
replace the sender in that tank, install new hoses & clamps while you are in
there but leave the old sender in the front tank (that is as long as it is not
rusted away). Cut the trigger wire free from the sender and ground it
(connect it to ground). When you switch to the "aux." tank the gauge will
read empty and the "low fuel" light on the dash will come on. This light
now tells you that you have selected the aux. tank and you need to get fuel very
soon.
No need to read the front tank, if you switch to the tank, you must be low on
fuel & I think it would be nice to have a light that reminds you that you have
made this decision. I forget I have switched to the aux. tank and keep on
driving. You DO NOT want to run out of fuel with a 12,ooo lb. boat
anchor--- you cannot push it! Having a light on the dash tell you that you
are into the aux. tanks reserve will remind you to stop.
Some "low fuel" light circuits do not work, the stand alone circuit may have become defective-- no problem, cut the white trigger wire to the low fuel light on the tell tale connector and tie it to the black wire on the fuel switch. The black wire is the trigger wire to the fuel selector solenoid and will manually turn on the "low fuel" light whenever the aux. tank is accessed. you can tie the front & rear tank trigger wires (light tan & light tan w/ white stripe) together and allow the gauge to see the main tank all the time. This way you will read the fuel level until the 1/4 tank lever just as before but will not see the 6 gallons left in the front tank, but you will still have access to it through the selector valve. This rewire saves you the @125 for the second tank sender that reads the same as the other one.
You should look at the aux. tanks as a reserve and this new circuits logic goes along well with that thinking--- and saves you money. If you have any other questions about this circuit, give me a call.