Car not starting if it sits
 

The 66 GTO will not start up if it sits for 3 or more days, without pouring gas into the carb. It has the 4 bbl Carter carb with auto transmission. I think what is happening is the float bowls somehow loose fuel. If I start the car every day I do not have this issue. Any idea how to correct the problem? I posted this in the street forum first, but thought that this might be a GTO specific problem. I don't think that these cars did this when they were new. I read before where others said they had the same issue, but never saw a fix for it. Any help is greatly appreciated.

If it helps any mine does the same except after a week or more of sitting idle.

Sounds like it may be bleeding thru the jets. Had the same thing happen to me back in the day with my 66 goat. Replaced the AFB with a dual feed holly and never had the problem again.

I've only rebuilt one Carter carb and I can't remember if it had the well plugs found on Q-Jets...If it does, they sometimes leak. If not, I'm going to paste something here that I ran across on Jon Hargrove's troubleshooting page- I have found his first scenario to be true even with carbs that I KNOW don't leak through the well plugs. The fuel just evaporates and you have two choices. Prime or crank.

http://www.thecarburetorshop.com/Troubleshooting.htm

HARD STARTING, COLD


Difficult starting a vehicle that has been allowed to sit for a number of days (that will then start well the rest of the day) is often caused by modern fuel. Modern fuel begins to vaporize (evaporate) at a much lower temperature than fuel before the 1970’s. Once the engine is shut off, the fuel in the carburetor bowl begins to evaporate through the bowl vent. If there is no fuel in the carburetor, the engine will not start. Pumping the footfeed during this time simply prolongs the agony, as the accelerator pump will pump the fuel into the engine, but in amounts insufficient for starting. If you have this problem, try priming the carburetor by using an eyedropper and filling the carburetor bowl through the bowl vent prior to cranking the engine. If you do not wish to prime the engine, crank the engine for 15 to 20 seconds WITHOUT PUMPING. Then stop cranking, pump the footfeed 3 or 4 times, release it, and then reattempt to start the engine. Priming eliminates excessive wear on the starter.



HARD STARTING, HOT


Difficult starting of a hot vehicle from 5 minutes to an hour after the engine has been operated, can be caused by the volatility of modern fuel. If you have this problem; try using the following method to start the engine: DON’T touch the footfeed (VERY important). Crank the engine over from three to 5 seconds (different vehicles will respond to different times); and then GENTLY (so as not to activate the accelerator pump) press the footfeed approximately 1/3 of its travel. The engine should start, and may run rough. Run the engine at a high idle for about 10 seconds. This issue is caused by volatility of modern fuel. Once the engine has been shut off, the gasoline is heated by the latent heat of the engine, and percolates the fuel from the bowl into the throttle area, forming a mixture that is too rich to fire. If you push the footfeed to the floor (as has been the traditional method of “unloading” a flooded engine) the gasoline continues to flow into the engine (again due to the volatility). By not touching the footfeed, you do not open the throttle plates, and the engine will pump the overrich mixture out of the tailpipe. Once the overrich mixture has been alleviated, gently opening the throttle will allow the engine to start.

Is this before or after a rebuild of the carb Charles?

With todays E10 gas, the ethanol will eat up the rubber innards and cause problems. Get a newer rebuild kit that's compatible with E10 and rebuild it if you haven't already. It should solve your problem. Or get a Weber built Competition Series Cater AFB. I have one on my 66 and I love it. To me it's a better carb than the original Caters and way better than the Edelbrocks. Weber did a great job with these carbs. I also have one with an electric choke sitting out in the garage.

There are no rubber parts in an AFB. Accelerator pump is leather and tips of needles are Viton. If your car won't start after cranking a little then the fuel pump won't pull the gas from the tank. If you let your sit for long periods of time (not a good idea) install a supplimental electric pump back by the tank. If you don't like it running all the time use a switch to turn it off once the car starts.

That's an interesting thought. It take that you're talking inline with the mechanical pump?

I had the same issue with my 67.
I rebuilt the carb. Replaced the fuel pump. Tried a different carb. Nothing changed.
I eventually found a small length of rubber hose connecting the fuel tank to the steel fuel line. The rubber had dried and had small cracks in it. Replacing the rubber solved the problem.
I think when the engine was running the fuel pump was able to overcome the small air leaks, but when only cranking at start up, it could not pull enough fuel.
I hope your fix is this easy.

Jim

If it's that hose Jim, I'd think he'd see some drips from gas leaking thru it when the car sits for any length of time. Maybe not tho. It did on mine but the car would always start when I used the manual choke. :confused:

I had the same problem with my Rochester Quadrajet. I had it rebuilt but the problem still existed. Then, I bought a newly re-manufactured one from Carb Specialties or Specialists in Atlanta. I can let my car set for a week now and it only takes a pump or two on the gas pedal and the motor fires right up.