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Stalls like it is out of gas- vapor lock?

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G0Bigred Avatar
G0Bigred JD Wyborny
Winterville, NC, USA   USA
1960 Austin-Healey 3000
1976 MG Midget 1500 "The Midge"
I have a 1960 bn7 that sometimes stalls and acts like its out of gas after driving when warm. I am able to start it right back up afterwards though. It is also very had (sometimes impossible to start) if I try to start it after leaving it warm for 5 minutes. Trying to figure out what might cause this, vapor lock maybe? I have recently replaced the gas tank, fuel sender, rebuilt the carbs and performed an oil change.

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G0Bigred Avatar
G0Bigred JD Wyborny
Winterville, NC, USA   USA
1960 Austin-Healey 3000
1976 MG Midget 1500 "The Midge"
Also car has only 700 miles on complete rebuilt motor. All parts are brand new when the car was restored 12 years ago.

sliproc Avatar
sliproc Kevin Quistberg E
Long Beach, CA, USA   USA
JD,

If it is vapor lock it's usually caused by the gas line being exposed to excessive heat at someplace in it's run. Insulation of the exposed area will usually solve the problem.

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G0Bigred Avatar
G0Bigred JD Wyborny
Winterville, NC, USA   USA
1960 Austin-Healey 3000
1976 MG Midget 1500 "The Midge"
True. Ill see if that helps. I can hear the fuel pump clicking harder when it is about to stall out.

rusty1c Avatar
rusty1c Peter D
Antioch, CA, USA   USA
1961 Austin-Healey 3000 BT7 "RUBY"
1963 Chevrolet C10 "Rusty"
JD,
One of the problems that some owners have with vapor lock is caused in the fuel pump area. If you notice the exhaust pipes are routed right below the fuel pump. When in traffic without air flow to keep things cool the heat can rise and heat the fuel lines and the pump. This can cause the vapor lock the you speak of. Some owners have moved the fuel pump to the bulkhead on the passenger side of the car with good results.
Also check the position of the fuel supply line in the engine compartment to make sure it isn't mounted to close to the exhaust manifold or the head pipes.
Pete

G0Bigred Avatar
G0Bigred JD Wyborny
Winterville, NC, USA   USA
1960 Austin-Healey 3000
1976 MG Midget 1500 "The Midge"
That sounds like that could be the issue judging by the fuel pump furiously pumping before it stalls.

RAC68 Avatar
RAC68 Raymond Carbone
NJ, Jersey Shore, USA   USA
Hi JD,

Although vapor lock is a strong possibility, I would not dismiss dirt in your pump or both. It is not uncommon for an old or new tank to contain debris from dirt in the fuel to manufacturing debris in the new tank. Although the SU pump could pass rocks and boulders, plastic sheet and paper could be enough to reduce or even stop fuel flow. Many have placed a filter in front of the pump by severing the fuel line from the tank. Although this will stop debris from entering the pump, what is often forgotten is that the tank/fuel-sending-unit uses the metal fuel line as a ground when connected to the pump (and its mounts). Additionally, as apposed to the BJ8's fuel path which puts the pump on the right side of the car and has the fuel line pass forward on the inside of the right frame rail and to the left side via the front cross member (below and back from the radiator), as I remember, your path is forward on the inside of the left frame rail protected from exhaust heat. However, it does pass upward when at the engine bay and is now more exposed to exhaust manifold heat.

JD, before I start working on a vapor lock resolution, I would first check the carburetor bolls and make sure the screens to the float chambers are clean and the floats are properly set. Also, checking the pump and/or fuel filters (if you have installed any).

Just my thoughts,
Ray(64BJ8P1)

G0Bigred Avatar
G0Bigred JD Wyborny
Winterville, NC, USA   USA
1960 Austin-Healey 3000
1976 MG Midget 1500 "The Midge"
All valid points. I do have a fuel filter between the tank and fuel pump and had the carbs rebuilt. I just checked and I’m actually out of gas which means I am averaging under 10 mpg. My guess is the fuel is being vaporized at and before th pump. I’m going to try insulate the exhaust pump under the fuel pump.

rusty1c Avatar
rusty1c Peter D
Antioch, CA, USA   USA
1961 Austin-Healey 3000 BT7 "RUBY"
1963 Chevrolet C10 "Rusty"
JD,
Just another thought. Check to make sure your fuel pump isn't sucking air as this will give you the same result as vapor lock, the appearance of running out of fuel. I had this problem and I found that the pump was sucking air . I traced the leak to the fitting on top of the gas tank. Even though the nut on the fuel line was tight it was sucking air in around the threads. I wrapped a bit of Teflon tape around the threads on the pipe coming out of the tank, reinstalled the fuel line and have not had a problem since.
Pete

G0Bigred Avatar
G0Bigred JD Wyborny
Winterville, NC, USA   USA
1960 Austin-Healey 3000
1976 MG Midget 1500 "The Midge"
Thanks. Plan on looking at this as well.

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