Intrepolicious
Well-Known Member
Of course I should probably wait until it's almost empty lol
I made that mistake once with my LH body.
I made that mistake once with my LH body.
I think you should replace the jumper at the back and quadruple clamp it, and if you already have done that, then take the cap off and throw it in the trunk for an hour.
What I think, with twice at the same-ish liquid level,either the pump is sucking air or the tank is not venting.
And before you replace the pump, do a volume output test. If you have to take it off,check the arm return spring first, before condemning it..
If there is junk in the tank, that makes it thru the sock it will end up in the filter.If it makes it thru the filter, you are in need of a better filter. Fine powder that makes it thru the filter while uncommon to me is a non-issue; it will coat the bottom of the bowl, no big deal. And if it makes it into the slow-speed system, it is too small to do any damage. It is iron oxide, it burns in the chamber.It makes a nice bright flash and then it is consumed.
If removing the cap solves the problem, you will have to troubleshoot the venting system.
Those are the things I would do.
This is the 4" or so short rubber hose that jumps from the tank sending unit to the main line. From the factory there is one flat band spring clamp on each side. These are the best. If they are no longer there, then gearclamps will work. Install two on each side and stagger the screws 180*. Do not over-tighten them.AJ, when you say "jumper at the back".. where exactly is that? On top of the tank?
I'm not saying this is or these are your problems, but I do think there is a very strong possibility. The tiny steel line that vents to the charcoal canister is well known to rust up, and the jumper doesn't last forever.I think you should replace the jumper at the back and quadruple clamp it, and if you already have done that, then take the cap off and throw it in the trunk for an hour.
Thanks AJ. Can that jumper be accessed without pulling the tank?This is the 4" or so short rubber hose that jumps from the tank sending unit to the main line. From the factory there is one flat band spring clamp on each side. These are the best. If they are no longer there, then gearclamps will work. Install two on each side and stagger the screws 180*. Do not over-tighten them.
When this jumper rots, it may not leak fuel cuz it is higher than the liquid in the tank. But the pump will suck air here, along with whatever fuel it picks up from the full tank. As the fuel level in the tank drops, it becomes harder and harder for the pump to lift the fuel up and over, so eventually the pump only pulls air, and everything comes to a halt. If the venting system also is not working, then this is likely to occur early and often.Remember, atmospheric air in the tank is what pushes the fuel up into the line. No air,equals no push.
When you let it sit, all the air in all the lines rises up towards the ends, and all the fuel settles in the low spots, and the tank pressure equalizes with the atmosphere. If the tank vent is completely plugged, then the tank may become pressurized by vapor pressure, which is the same process which makes your plastic jerry-cans swell up in the sun.
So now you go to start it and vapor pressure is forcing the fuel along in response to the pumps pull. Pretty soon the pump has got a prime and it fills the bowl, and the engine springs to life. So off you go happy as can be. Some undetermined time later, depending on many factors, the vapor pressure may drop to zero, and the pump starts pulling air, and the whole thing crashes again. And that's why I said
I'm not saying this is or these are your problems, but I do think there is a very strong possibility. The tiny steel line that vents to the charcoal canister is well known to rust up, and the jumper doesn't last forever.
The way you describe it, it sure sounds like it. Especially because the same exact thing happened before with this specific amount of gas in the tank.I'm not saying this is or these are your problems, but I do think there is a very strong possibility.
I think your 2nd thought is spot on with AJ's. I'm going to have to take a look at this jumper.Two items popped up in my head.
If engine is running hot (carburetor too hot to touch after turn off), sometimes fuel can percolate out of the carburetor bowl. Generally fuel will remain in the accelerator pump circuit – so you have one or two shots of fuel - but other than that, it takes a while for fuel to re-fill the fuel bowl before car will run (vapor lock).
Second thought is if you have a rusty fuel line or cracked fuel hose, an air pocket will develop in fuel line. Fuel pumps prefer to pump liquid and not air, and it takes a while to pump air before fuel gets where it needs to go. Generally the fuel line after pump to carburetor still has fuel as well as fuel in carburetor – so maybe 15 seconds of fuel (or more) after startup, maybe?
Might even have both conditions.
BudW
I don't suppose you've got a picture of this do you AJ? Again, do I need to drop the tank?This is the 4" or so short rubber hose that jumps from the tank sending unit to the main line. From the factory there is one flat band spring clamp on each side. These are the best. If they are no longer there, then gearclamps will work. Install two on each side and stagger the screws 180*. Do not over-tighten them.
I realize that the gas cap I have is "vented" but wonder if it's working right.. when I remove it, it's definitely releasing a lot of pressure. Like a soda bottle!Well, I got off my lazy butt and went and looked. Yes, I'll definitely have to drop the tank to get to this jumper.
Too bad they didn't make an access panel in the trunk.
AJ, do you think a vented gas cap might alleviate some of these vapor locking issues for the time being?
Could go either way, depending on the jumper,Well, I got off my lazy butt and went and looked. Yes, I'll definitely have to drop the tank to get to this jumper.
Too bad they didn't make an access panel in the trunk.
AJ, do you think a vented gas cap might alleviate some of these vapor locking issues for the time being?
Could go either way, depending on the jumper,
But before you drop the tank, you have got to prove a couple of things, namely that it is in fact a fuel issue. If you drop that tank and find nothing wrong, you are gonna be one unhappy guy, and I and everyone else is gonna hear about it.
You haven't proved anything yet. I, and Bud, and others, are just throwing out ideas based on our experiences.Somebody still has to prove it, and I'm not the one,lol.
Besides, you may be experiencing multiple issues.
An engine needs 7 things to run. You already know about 3 of them,namely fuel air and spark.Besides these; it needs compression,a reasonably close AFR, she needs to process air OUT as well as in,and everything has to work according to the designers plan.
Since you drove it a fair ways before it croaked; It just did have all 7 of those. In your case, the most likely culprits are; a failed spark,or no fuel.Both of these are easy to prove. Spark is easiest.
So, the next time she croakes,immediately go check for spark.This is so easy.
And if it's there, then you check the carb for fuel. And just cuz when you pump it, something comes out the squirters, doesn't prove the bowl is full, and even if it was, What is it full of? Just cuz you pulled up to the gas bowser and filled up, exactly what went into the tank. You believe it was gas, cuz you've done it probably thousands of times. But was it 100% gas? People believe lotsa things, that doesn't make it true. People believe the earth is a ball
to be continued, I got company