Mechanics

CHEVROLET CAMARO GAS PROBLEM

1974 Chevrolet Camaro • 98,000 miles

Dear Sir

Would you be so kind to help me with a starting problem that I have from cold. I have a 1974 Chevrolet Camaro with a 350 ci and automatic. The problem I am having is that when the car is left standing for a month or so with out starting it is very hard to start. If I pour gas directly into the carburetor it will start straight away, but then die when the fuel has been used. Up I can then crank it up and it will start much easier after the fuel is poured straight in the carburetor.

The carb is a four barrel Holly 600cfm 1850. The fuel pump has been changed and is a new one. When I try to start it, the motor will keep cranking, but not fire. After a while it will kind of fire, then die. Pouring the gas in circumvents this starting problem. When it has started and is running, the starting is not a problem. Even when it is left for a at least a week it will crank and start.

This is my first time in writing to you and was recommended by a friend who does use your expertise.


Yours Sincerely

John

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Metropolitan
February 26, 2013.



The fuel is evaporating out of the float bowls and all the way down to the fuel pump. I have a similar problem with my '80 Volare but it's not quite that bad. If it sits overnight I will have a long crank time the next morning until it fills the float bowl, but when I purposely run it out of gas to check my fuel mileage, the pump will not draw a prime from the tank unless I also dump a little gas down the carburetor. It needs the higher rpm to start drawing fuel. That car often sits unused for more than a year. It has always started eventually on its own except for one time recently after it had been sitting on a hill for a few months. The gas tank was almost empty, and it needed a splash of gas in the carb to get started.

The solution for my problem was to install a check valve in the hose between the float bowl and charcoal canister. Mine was a common problem and that was the very effective factory fix. I have the part but never installed it yet. What you might look at is that hose going to the canister. Pinch that off when the car is going to be sitting for a long period of time and see if that helps.

Check on the bottom of the carburetor for any plugs that are leaking. If the floats drop, the gas could evaporate all the way down to the pump. Those plugs can be sealed with epoxy if you find a wet or stained one. They are just there for when they drilled passages, then the plugs seal up those access points.

Caradiodoc
Feb 26, 2013.