where does my fuel go

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Tadams

Tadams

Tadams
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I have just gone out to start my 1965 Barracuda. I had it running last week and it was fine. Today it didn't want to start so I opened the hood and notice the fuel filter has very little fuel in it. I pour a little fuel in the carb, the car starts and the filter starts to fill with fuel. My carb was rebuilt, I have a new fuel pump and the filter is new. The car is a Formula S with a stock 273 in it. The car is garage kept and there is no wet spots on the floor from leaking. I assume the fuel is leaking back to the tank, but why? How do I solve this? I would hate to go to a car show and have to put gas in the carb to get it started.
thanks for any ideas.
 
You can crank on it and it will fill the carb back up, but yes, that's a major embarassment.

My truck did that, too. I always figured the AVS had a crack in it somewhere or maybe the fuel was evaporating out. Then I put in an electric pump and the noise is a soothing reminder that my carb is full.
 
It evaporates from my cars with carburetors. If they sit more than one day, I have to crank the engine for several seconds to refill the carb. It seems to be more of an issue since they added alcohol to the gas.
 
It does that to mine too. Even different carbs and a new fuel pump didn't help. I crank the motor for 10 seconds or so before I set the choke. It helps build oil pressure before the engine fires too. Thanks for reminding me. it's time to open up the storage garage and start my car today. tmm
 
Thanks guys, I had thought about the electric fuel pump but didn't think it was an issue. The car seems to take quite a while to start. I hate to sit and grind on it for a few moments to get it started. Once it has started it starts real easy.
 
Thanks Mike. I read your post on the points conversion and ordered mine from Summit last night. The dual point in mine work fine, but after reading your post I felp like it would be an advantage. Thanks. I need to finish repalcing the wheel cylinders on mine today, so I was going to back out of the garage when I noticed this problem.
 
I threw in the towel on my 67 and did three things

1 installed an electric pump, and for now am pumping right through the mechanical pump.

2 Ran a return line back to the tank, brazed a tube into the tank, and used a Wix fuel filter for a vapor return. REALLY helped on hot days

Wix (and others) make at least two vapor return filters, one 5/16, one 3/8, Wix numbers 33040, 33041

3 Got some nice think isolator gasket/ spacers and stacked under the carb. I think I have about 3/8 under there and that helped, too.

All this helps in a couple of ways. I recently fired up the Dart on a cold, dry winter day. About 20-25*F. I don't have the choke hooked up, so I just turned on the key and waited maybe 5 seconds for the pump to fill the carb, pumped the gas about 4 times and it was fired.

On hot days, it prevents hot "no start" problems, fuel boiling, vapor lock
 
Thanks, I think you guys have convinced me to go with an electric fuel pump. I need to finish the brake project before I start something else.
One question, I looked on line to check on the fuel pumps and noticed there are different fuel presures availiable. Which one would I need?
Thanks so much for your help
 
I just crank it for a few seconds then pump the gas once and crank it again starts right up not an issue for me,never had an issue when warm.
 
Hi Lou, If mine would do that I would be OK. The issue is I can crank for 2 minutes or more and it still doesn't want to start. I have cleaned the tank, the lines and replaced the fuel pump and It is the same. Thanks for the update. Have a great day.
 
Tadams said:
Thanks, I think you guys have convinced me to go with an electric fuel pump. I need to finish the brake project before I start something else.
One question, I looked on line to check on the fuel pumps and noticed there are different fuel presures availiable. Which one would I need?
Thanks so much for your help
Click to expand...

I bought a small draw through electric pump from NAPA [around 35 dollars] to "prime" mine with. Same issue here, today's gas evaporates very quickly. I installed mine and hooked it to a toggle switch to get it started and then I just turn it off. It's a little noisy, but you don't have to sit there and crank it forever.

I was curious, so last summer I put 1 inch of gas in a spray bomb cover and left it on my work bench, 24 hours later it was gone!
 
If my Cordoba sits more than a few minutes, i have to crank it a while with my foot on the floor before it starts..... :(
 
Mechanical fuel pumps have a check valve that keeps the gas from returning to the tank. They can get leaky. Also the alcohol added to gas evaporates quickly.
 
KitCarlson said:
Mechanical fuel pumps have a check valve that keeps the gas from returning to the tank. They can get leaky. Also the alcohol added to gas evaporates quickly.
Click to expand...
X2. A hard hot start is usually percolation which causes a slightly flooded condition.
 
cudamark said:
X2. A hard hot start is usually percolation which causes a slightly flooded condition.
Click to expand...

And THAT is part of the reason that vapor return systems WORK. They immediately relieve fuel line pressure, preventing the fuel in the line from forcing more into the carb bowl, and boiling over into the bores.
 
another possibility is similar to the guy with the crack in his carb... when it was rebuilt, one of the gaskets might be allowing air to draw back through and lets it drain from the carb back into the tank.

if it was me, i would see if could find a carb on the cheap somewhere, same model. get a rebuild kit and get it all soaked and cleaned and every orifice clean as a whistle. put the rebuild kit in it. when you are all done you can swap out the carb and i bet you will see a difference

did the problem first start after the carb rebuild?
 
I've been into hundreds of carbs Very few of them had cracked bodies. Even after someone broke a mounting ear off, cracks/ leaks are pretty rare.

I guess they improved TQs, but the early ones had problems with body warpage

Quadrajets used to have a certain problem with the bottom plugs leaking, that became a "preventive" fix--epoxy 'em up, and the kits used to come with a foam gasket was supposed to fix it.

I've had quite a bit of trouble back in the day with Holley power valves, and have even seen "leakers" right out of a quality kit. This includes Blue Streak, NAPA, and Holley
 
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