Two Fuel Tanks

jay leighter · #1 (**permalink**) 10-03-2004, 11:08 PM

I just got a '73 SCS F350 with two fuel tanks. Is the main the front tank or the rear tank? And, the valve on the floor next to the driver...there are three "settings," which one goes to which tank? I'm having a hard time figuring this out, partly because I don't think the valve on the floor is working.

Thanks.

Mil1ion · #2 (**permalink**) 10-04-2004, 12:54 AM

The main tank is the one between the frame at the Rear of the truck.

The auxillary tank is the front one mounted sideways.

73f350sc · #3 (**permalink**) 10-04-2004, 01:00 AM

Hey Wecome to FTE,
I have one just like it. The rear tank it is the main the one closest to the cab should be the aux. As for the positions if the handle is turned toward the seat so the small pointed end is pointing toward the rear of the seat its in the aux. position , if its pointing straight toward the rear of the cab its in the off position and pointed forward is the main tank. There should be a black plate at the base of the valve that has the positions marked on them you may want to see if you have one and its just dirty. Thats what happened to me, it can kinda be tricky to tell if theyre working or not. i did it by just filling one tank for a while that way if I ran out it would tell me whether or not one or the other was working you can also pull the lines off one at a time and ee if gas comes out. Enjoy your truck its a rare model so take care of it, and let us see some pics too.
-Chris

biggreen78 · #4 (**permalink**) 10-04-2004, 12:27 PM

heres one for ya... after i bought the truk, on my way home I ran out of gas...(I filled both tanks completely up right after leaving the sellers home)...after dreading my gas mileage (only went about 200 mi off of $60 gas...or so I thought...the rear tank was still filled up) I poured even more gas in the rear tank (obviously not knowing it was still full) with all of the 2 1/2 gal that the crappy can could hold, but the truk did not start, i went all the way back to the gas station, and all the way back again and this time filled up the "auxillery" tank to which the truk started right up
to this day, I only fill up the mid tank and all is well
I noticed that the rear tank leaks gas and the tank selector switch when flipped to aux drops the gauge to empty immediately even tho it could be full of gas...how is this explained other than some redneck engineering

ranger429 · #5 (**permalink**) 10-04-2004, 02:53 PM

Maybe the selector valve is bad? It should be mounted on the driver's side inside frame rail at about the start of the front of the box.

quadrazer · #6 (**permalink**) 10-04-2004, 11:04 PM

Quote:

Originally Posted by biggreen78

heres one for ya... after i bought the truk, on my way home I ran out of gas...(I filled both tanks completely up right after leaving the sellers home)...after dreading my gas mileage (only went about 200 mi off of $60 gas...or so I thought...the rear tank was still filled up) I poured even more gas in the rear tank (obviously not knowing it was still full) with all of the 2 1/2 gal that the crappy can could hold, but the truk did not start, i went all the way back to the gas station, and all the way back again and this time filled up the "auxillery" tank to which the truk started right up
to this day, I only fill up the mid tank and all is well
I noticed that the rear tank leaks gas and the tank selector switch when flipped to aux drops the gauge to empty immediately even tho it could be full of gas...how is this explained other than some redneck engineering

dual tank valve

--------------------------------------------------------------------------------

When I switch from the back tank to the front tank, my fuel gauge switches but I still draw from the rear tank. Kinda the same problem you have just opposite tanks!
The problem with mine is the fuel tank selector valve, which selects which tank fuel is drawn from. This is obviously seperate for the tank selector switch in the dash. Just thought you would like to know.

jay leighter · #7 (**permalink**) 10-05-2004, 02:11 PM

It's precisely why I asked the question...the situation you just described. The sender was working in one tank (for the gauge) and the valve was working for the other (to get gas to the engine). The ford dealer got the valve working for my, so now I can get gas from both tanks. Wasn't expensive at all. I can live with the bad sender in the main tank. After posting my question and figuring out which tank was which (thanks guys), I'll just fill both tanks, run the main until it's empty and finish on the aux...the tank with the working sender. So long as I do that, I should not run out of gas...again.