The Stovebolt Site Forums The Shop Area Engine Shop Fuel tank

I have an original style fuel tank behind my seat (51 3100). The other day, I “ran out of fuel” or so I thought. I put in 2 galllons to get home and an extra gallon I had at home to ensure I had no issues making it to the gas station. When I got to the station, I was only able to fit in 6.5 gallons before I was full (I could see fuel in neck). If that’s the case, I only put in 9.5ish gallons.

My question: is it typical with a gravity fed tank (without baffles) to run out of gas with 3.5ish gallons left in the tank on flat land? If so, I’m curious to hear how others work around this living in hilly or curvy country roads.

Please don’t tell me to add fuel! I normally don’t let my tanks get this low!

Thanks,

Chris

The outlet of the tank is likely plugged with crud. I've had that happen on another vehicle. The rust flakes line up over the outlet and stop the flow.

You can probably get going again (temporarily) by removing the line between the tank and fuel pump and blowing air into it.

[on edit] the act of adding fuel may have removed the obstruction (again, temporarily).

1. Drain the tank.
2. Remove the sending unit.
3. Peek inside with a flashlight and look.
4. Use a small shop vac to suck out the debris.
5. Clean the line to the fuel pump.
6. Replace any soft lines from tank to pump. They tend to deteriorate from the inside.

When I replaced my rusted tank, I installed a new petcock and new hard lines from tank to carburetor. I really dislike rubber fuel lines of any kind.

When shopping for a new fuel tank, which you probably need, buy the Canadian made Spectra tank. It's inexpensive and better quality than the original.

And in answer to your question, the gravity feed tank makes it possible to run every ounce of fuel out of it so an empty tank means that 18 gallons will fill it up.

Some have taken the approach of installing the later, task force series, sender in the earlier tank. Would take some replumbing and perhaps a new floor penetration.

So I replaced the tank a few years ago, so tank is clean and new, (I replaced the sender a few months ago when tank was empty. There was no rust in the tank at that time and no observed garbage.) gas is a few weeks old and normally kep full, fuel filter was replaced this past winter when I do my yearly maintenance.


Unless something drastically happened to my tank, I feel confident my tank is not rusted. Potentially, something could be in my tank from filling fuel.

My issue happened as I was accelerating around a corner and going up hill.

Chris

What about the petcock and fuel lines?

What made you think your fuel tank was empty?

Was there no fuel in the glass bowl on the fuel pump? Was no fuel reaching the carburetor?

If your fuel tank was full but fuel wasn't reaching the carburetor, the problem lies somewhere in between.

Prior to putting my new engine (261) in, I blew out all the lines with my compressor. The lines/petcock were all replaced at the same time as my tank.

I couldn’t tell if there was fuel in the carb (didn’t have my tool kit and I was on a busy highway.) my buddy brought a fuel can and she started up after I got her primed and air out of lines. Only had minor sputters on the way home and drove her today with a full tank and she ran great. I didn’t touch anything else.

Chris

Edit: fuel is not red when put in a glass jar

Let's look at the other end of the fuel system. Trash in the line to the carb could migrate to the needle seat and easily stop flow during an uphill acceleration, then fall out during idle when the float closes. Check the carb for trash in the inlet well. Do you have a filter at the carb?

Just grasping at straws.

I put my inline filter between the tank and fuel pump to protect everything downstream from the tank.

My gut is telling me that I sucked air into the line when the fuel shifted inside the tank.

Has anyone ever had issues fuel due to cornering or hills with a gravity fed tank?

Never. I've put 4000 miles on the truck in all kinds of driving over the last year or so. I've run my tank down to less than a gallon without trouble.

GM didn't build trucks that would conk out every time the fuel sloshed around in the tank. You had 20% of your fuel capacity remaining when it conked out. That's a significant amount of fuel.

You have some other problem. Keep looking.

That’s what I thought also! I’ll go through everything again!