Dies at half tank

I

izze

Member
I have been researching about my issue, but have not found a solid answer yet. My '30 coupe dies right at a half tank of gas. I remove the gas cap to make sure its not vapor lock. I have checked all the fuel lines, there are no clogs. I have looked down into the tank after it dies, and I do not see anything that is blocking fuel flow.

I replaced the shut off valve a while back, at which point I hooked up a copper line after the sediment bowl. The tank drained completely. So I do not see this being a fuel line problem.

I always carry a gas can now. When it dies, I put a gallon of gas in and it fires right up.

Can you all help me troubleshoot this?

Thanks,
Christopher
 
Izzie,
"Maybe" your fuel line extends too far beyond the ferrules, at one end or the other?? Should be only about 1/8". It can sometimes touch he screen in the top of the carb bowl, & "maybe" at 1/2 tank, the fuel pressure of the gravity flow system isn't enough to ovecome the restriction. Minerva's line was too long & was also touching the side of the screen filter's 1/8" wide, soldered seam. I've read that sometimes if the line's too long at the sediment bowl, it can cause restriction also?? As a test, when it fails, remove the plug from the bottom of the carb, turn on the gas, & see if you have GOOD flow out the bottom of the carb.
ALSO, once I had a restriction from a tiny black beetle, laying on top of the float valve, YES, he wuz DEAD!---Bill W.
(Izzie, did you put a standpipe filter in the top of your fuel valve? IT'S A MUST DO THING, ELIMINATES A LOT OF PROBLEMS!! Too bad Ol' Henry didn't think of that.)
 
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BILL WILLIAMSON said:
Izzie,
"Maybe" your fuel line extends too far beyond the ferrules, at one end or the other?? Should be only about 1/8". It can sometimes touch he screen in the top of the carb bowl, & "maybe" at 1/2 tank, the fuel pressure of the gravity flow system isn't enough to ovecome the restriction. Minerva's line was too long & was also touching the side of the screen filter's 1/8" wide, soldered seam. I've read that sometimes if the line's too long at the sediment bowl, it can cause restriction also?? As a test, when it fails, remove the plug from the bottom of the carb, turn on the gas, & see if you have GOOD flow out the bottom of the carb.
ALSO, once I had a restriction from a tiny black beetle, laying on top of the float valve, YES, he wuz DEAD!---Bill W.
(Izzie, did you put a standpipe filter in the top of your fuel valve? IT'S A MUST DO THING, ELIMINATES A LOT OF PROBLEMS!! Too bad Ol' Henry didn't think of that.)
Click to expand...

yea what dad said he's right on and also trained me:o
 
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Yes the old fuel line 1/8" too long trick. Was major part of my problem only mine would shut off after 40 minutes like clock work.
 
Interesting reading.... Full tank, maximum "head" in the fuel tank
(Fuel tower)... Wondering if this might have been my issue a few days ago..
 
check you needle and seat and make sure its not a model B, its for a fuel pump and
the A is for gravity. The model a should have a number 54 orifice the model b is a 44
 
The fuel gauge is reading correctly. When it died I took a look in the tank and it was about half full. A friend of mine rebuilds carbs. He gave me a spare to try out. I will make sure I'm only 1/8" when I install it tomorrow. And if it dies again, I will be sure to check flow out the plug on the carb. Good suggestion. And yes, I do have the stand up filter in my tank. Thanks for all the help. I'll come back with results from tomorrow's tests.
 
The next time it stops, listen very carefully when you remove the gas cap. Do you have a "woosh" sound? Your cap may not be venting and at 1/2 tank gravity won't overcome the vacuum caused by the un-venting cap. The woosh is the air sucking into the tank and she will immediately start and run some more.

Richard
Anaheim CA

Don't ask
 
I don't think it's vacuume in the tank. I tried starting the car with the cap off. No luck. Also drilled two more vent holes into the cap.
 
Hi Izze,

FWIW:

Just several experiences in Solving Engine Intermittent Problems: Engine "Go" ..... Engine "No Go" .... "Think"!

1. "Go": When the engine is running with absolutely no problems, there is really no engine problem to diagnose because with a suspected fuel starvation problem, the engine is supposedly obtaining constant fuel flow.

2. "No Go": When the engine stops, supposedly because of lack of fuel, this is really the time to investigate, to "think", & to try different fuel flow related things.

3. For example:

a. When the engine stops, try removing the gas line at the bottom near the carburetor to verify gravity fuel flow & it is important to allow fuel to run long enough to fill at least a half-gallon size container.

b. If slow fuel flow or no fuel flow, slightly loosen gas line 1/4 turn near fire wall filter connection, rotate gas line 180 degrees upwards, & blow in gas line a few times to verify if you can hear bubbles in the tank.

c. Next rotate gas line 180 degrees downward to verify if fuel flow is greater because of possibly blowing away debris around the fuel line where it enters the tank or clearing debris in gas line. If fuel flow is greater after blowing gas line, & tank was found to be dirty, drain tank a few times through a filter & add an in tank screen filter.

d. If a fuel flow problem is still observed, it is also possible that the fuel line or fuel shut off valve is partially clogged thus restricting fuel flow, especially when the tank is less than full & does not have enough pressure to overcome the debris blockage.

4. Just remember that all Model A seemingly unresolved Voodoo Problems are either mechanical, electrical, or fuel related -- unless the Model A owner is of the Voodoo Faith & fears "thinking" about attacking a Voodoo Problem.

Please let us know what happens after you try the above.
 
Do you get any symptoms of fuel starvation before it dies on you ( eg back popping thro carb?) or is it absolute and sudden death?
PS what happens if instead of taking time to put a more fuel in you leave the car for 10 minutes and have a beer? does it restart without problems? ( I had an MG with a fault that always resolved when engine had cooled down ; I spent the time tinkering with it thinking I was working a cure- could have spent the time having a beer instead)
 
I guess the only change you made was the shut off at the tank,no problem before? I would remove the new shut off and visibly check it to make sure the hole in the stem is open completely when you turn the handle,possible sediment in the tank is clogging the whole,if you changed the lines go back over them.
 
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