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My 1970 Maverick has spent more time in my driveway than on the road! I’ve been having trouble with it stalling whenever I gave it gas, after stopping at a light and going around corners. I had the carb rebuilt by a friend who is quite knowledgeable about old Mustangs. He spent some time trying to solve the problem by adjusting the idle, but this didn’t really help. I decided to change the fuel filter, put a new fuel pump in and even attach an additional fuel filter to the fuel hose on the tank side of the fuel pump. None of these changes worked. Are there any avid Ford Guys/Gals that might know what the problem might be? Thanks.
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It sounds to me like the accelerator pump in the carb. Sometimes the pump well in the casting gets so worn that the pump seal won’t seal against the well bore anymore. With the engine off, look down the carb throat while actuating the throttle. If the accelerator pump is working correctly, you should see two strong streams of fuel spraying into the primary throttle bores while the throttle lever is being pushed back.
I took a look down the carb and did get a stream of gas coming out of the jet, I’m assuming there is only one jet on this carb. The Maverick has an inline six. I can drive the vehicle if I baby the gas pedal and be careful not to accelerate too suddenly. Is it possible that there might be a vacuum leak causing the problem? I haven’t checked for this yet. Thanks
Yes, the inline six will only have one accelerator pump jet for the single barrel carb. I’m wondering now if your vacuum advance line to the distributor is disconnected or leaking. Has the engine backfired at all?
I think you might have the exact same carburetor as the one I have.
My guess is it’s fuel related. Either the carburetor didn’t get set up correctly, or there may be a vacuum leak as you suggest. This might help in finding vacuum leaks.
You might also want to check the engines mechanical condition, including for timing chain slack.
More info on performance diagnosis here. BTW it also includes a video on compression testing.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
Good luck and keep us posted.
Another thing to check is the accelerator pump linkage itself. Many carbs had more that one attachment slot for the pump linkage, and it’s possible your linkage might be attached to the wrong slot, which would vary the rate at which the accel pump delivers extra fuel. You could be under or over fueling your carb during acceleration, and both conditions can cause a stall.
If you still have the instructions that came with the carb rebuild kit, they should specify which slot to use for your car.
Thanks for your response, T-Rex. No, I haven’t had any issues with the engine backfiring but I’ll check the vacuum advance tubing for leaks. I don’t know much about how the vacuum advance system works. (I’ll have to read up on this.) There’s a black circular unit behind the carb that I assume is part of this system. Perhaps isn’t set right. This unit was actually scabbed from another carb after the original unit broke when a mechanic friend dropped it while rebuilding it. I’ll definitely follow up on your suggestions. Thanks again for your advice.
That black circular thing is probably the housing for the thermostatic coil spring which opens the choke automatically as the engine warms up.
Yes, your right about that. Thanks for setting me straight, Evil-I. I’ll check out the suggestion you posted regarding the accelerator pump linkage on the carb. Thanks for your input.
Thanks, Eric, for all the resources you posted for me. Gone are the days of heading to the library in the hopes of finding literature that might be of help for a backyard mechanic. Your site is awesome! I’ve really appreciated the help I’ve gotten from you and the other members from the site who have been so generous in sharing their experience and knowledge! The neck of my carb is stamped “Carter” but it has a tag attached to it that says “Autolite”. I’m looking forward to viewing the videos you posted. I’m sure they’ll be a great help in tracking down the solution to this stalling problem which has been plaguing this vehicle for the last ten years. I bought this vehicle thinking it would be a great way to learn about cars without having to deal with computer technology. But It has been a frustrating relationship and things are now on thin ice. If I can’t get this thing fixed, it might have to go. Your site is my best hope in getting it back on the road as I can’t afford to pay someone else to tinker with it.
You are quite welcome, golver. I watched the vids that Eric posted, and they are very informative; they should get you going in the right direction. Just one more thing to add: If the fuel tank has never been replaced (or refurbished), there is a very good chance that the sediment and trash in a 45-year old tank could be blocking the fuel pick-up in the tank. If you can drain the tank and drop it down so you can get to the fuel sender, you can find out pretty quickly what the condition of your tank is by removing the sender and taking a look inside. I can probably count on one hand how many times I found that a bad fuel tank was the reason for a car’s erratic behavior. Best of luck, and keep us informed.
Do you know how he rebuilt the carburetor? The only proper way and one reasonably sure that it’s right is to soak it in carb solvent for an least an hour or two, thoroughly wash it out, and used high pressure air to blast every orifice in it along with air bleeds, jets, etc.
Another possibility is vapor lock. Older cars running on unleaded gasoline in summer heat are certainly prone to this problem.
Any chance there’s a vacuum leak or the ignition timing is not advancing due to a failed vacuum advance or stuck advance weights in the distributor?
Good question about the procedure used in rebuilding the carb. The most recent work done on it was by a good friend of mine. I’ll have to ask him what he did exactly. I’ll also pursue your suggestions about a possible vacuum leak and ignition timing problem. Lately, I’ve been inundated with work and unable to spend any time with the vehicle. Hopefully, things will settle down next week and I will be able to look into the suggested causes offered by the site members. Thanks Bluesnut for yours, I’ll let you know what I find.
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