Running out of gas with a full tank

chope97

chope97

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Silver Spring, MD
Twice in the last month my car has run out of gas after driving around for a couple of hours. It starts fine and I can drive it around for a while but then it will start to loose power especially after I stop at a store go in for maybe 30 minutes. I come out and it might be a little hard to start. Then I get it started and start driving about 20 feet and the car looses power. Yesterday I drifted it back into a parking spot. I opened the hood and sprayed starter fluid down the carbs. The car runs for a a few seconds. I took a fuel hose a loose and no gas came out. The gas tank is full. I checked all the fuel lines hose clamps. I did find one clamp that was not tight. I kept cranking the car until I see gas coming out of the disconnected hose. I reconnect the hose and eventually the car starts and stays running. Everything is back to normal and I drive home. This was a very hot day. My fuel pump is new. Could this be vapor lock because of the heat? Could the loose hose clamp be causing the problem? I am thinking of switching to an electric fuel pump.
 
I have discovered that “new” doesn’t always mean “functional”. If it’s that new maybe get another one during the return period, but the lack of fuel coming out certainly points to an intermittently functioning fuel pump.
 
It sounds like one or more of these:
Plugged filter
Plugged or collapsing hose
Sediment in the pick-up or float assembly
weak fuel pump

Since you have already found that the pump is not delivering a stream when cranking I suspect the pump.

Check your fuel pump volume by getting a clear bottle and cranking the engine allowing fuel to pump into the container. You should have a steady stream of fuel.
 
Looks like your weather has been in the mid 90s. After sitting 30 minutes and not running for long after restarting, I would suspect vapor lock.
 
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My 2 cents…

To minimize vapor lock, make sure NONE of your fuel line is higher than the fuel bowl inlet. That is a prime setup to create vapor lock. It also helps to route your fuel line away from hot spots and direct heat sources.
I once had a VW where the gas tank vent was plugged. It would run for a while and then die due to the vacuum created in the fuel tank as fuel was being used!

And FWIW… while we are talking about typical problems, I see most Weber carb conversions have an open half-inch hole at the front of the carb. I believe Weber already added redundant internal vents elsewhere, meaning that big front hole is completely unnecessary. If you plug that half-inch hole with a rubber plug, you will never have empty float bowls again. My car can sit for months and fires right up with no priming.

I think that stalling after a few minutes of driving is also a symptom of coil overheating or condenser failure?
Or perhaps float is sticking and is fuel bowl empty?
 
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