71 Duster 340 carb issues? Maybe

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BrianR

BrianR

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Arlington, tx
Hey All,

Looking for some guidance. I have a 71 Duster 340 4speed. The car will run and drive great. But it seems like when I run it for a while it will die and the only way I can get it to start again is to damn near push the pedal constantly to the firewall. The carb is a quick fuel 750 with no choke and vaccum advance. I'm running msd igniton and a MSD distributor. Could it be the accelerator pump lever or something with the carb? Any help is great. Thank you.
 
Check fuel lines and fuel delivery items if you haven't already.
 
BrianR said:
I have a new Carter fuel pump and sending unit.
Click to expand...

Is the fuel filter before or after the fuel pump? Also, would there be anything blocking fuel delivery? If not, then a carb issue.
 
check to see if the vent in tank is working / check fuel filter on pick up this can be done with a fuel volume test
 
I put a new fuel sending unit. Clit has a clean screen. I had it running and pulled the gas cap off the tank and I didnt hear any suction. Now one other question. So when I replaced the sending unit there was the hose fuel to pump and then a nipple that was capped off. Should I not have capped that off?
 
Get a good flashlight look down the primary barrels of the carburetor as you give it a couple quick pumps you should have a strong flow of fuel from the accelerator pump. You could also put a clear fuel filter in the line near the carburetor to assure you of adequate fuel to the carburetor. Also check the site bowls after it's been running to make sure that you don't have a float problem. Do this with the motor off after running for a while.
 
What is the rest of the story.
A carb with no choke, what else is not stock. What about the engine build ? Stock or not.
Accelerator pump only does something if you are pumping the pedal. Nothing to do with constant running.
Complete answers need complete information.
 
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Yup, flooding. Clue is the requirement to floor the throttle to start the engine.
 
How hot is the engine when this happens?
 
Insufficient initial timing doesn't require the throttle to be floored sometimes to start & then start normally at other times....
 
Stopped and idling;
>If it is running out of fuel , and the fuel level started out close to correct, it will give lots of warning. As it goes lean the idle speed will go up a lil, level off then rapidly slow until it sputters to a stall.
>When an engine begins to flood, at an idle, it rapidly slows down and struggles then stalls sometimes puking a fuel cloud up thru the carb backwards.
>If it just flat quits, that is much more likely to be an electrical issue.
>If the engine is overheating, because the ring gaps are too tight, the engine, from an idle will just slow down until it quits without any drama. If you attempt a restart right away, it will crank slowly if at all. If you leave it cool for twenty minutes or so, it may crank normally and fire right up, unless it has cooked the gas out of the carb.
>If your fully warmed up engine is putting steam into the tailpipes on a normal-humidity day, with a fully warmed up exhaust system, this could be bad news. If you are simultaneously loosing coolant with no signs of leakage, it may be going into the combustion chambers. This will cool the chambers and affect carburation; as the chambers cool, she will want more fuel. Making steam take a huge amount of energy.
>Many times it happens that after you replace the fuel level sender and that little short jumper-hose, that you might have Not re-used the factory spring clamps. If you have used gear clamps, thinking they are better, that is a wrong thought. Gear clamps that small, have to be used in pairs, with the heads rotated about 180 degrees, so that the pump does not suck air from the gap that just using one clamp, creates.. That jumper needs 4 gear-clamps in total.
Good luck
 
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AJ/FormS said:
Stopped and idling;
>If it is running out of fuel , and the fuel level started out close to correct, it will give lots of warning. As it goes lean the idle speed will go up a lil, level off then rapidly slow until it sputters to a stall.
>When an engine begins to flood, at an idle, it rapidly slows down and struggles then stalls sometimes puking a fuel cloud up thru the carb backwards.
>If it just flat quits, that is much more likely to be an electrical issue.
>If the engine is overheating, because the ring gaps are too tight, the engine, from an idle will just slow down until it quits without any drama. If you attempt a restart right away, it will crank slowly if at all. If you leave it cool for twenty minutes or so, it may crank normally and fire right up, unless it has cooked the gas out of the carb.
>If your fully warmed up engine is putting steam into the tailpipes on a normal-humidity day, with a fully warmed up exhaust system, this could be bad news. If you are simultaneously loosing coolant with no signs of leakage, it may be going into the combustion chambers. This will cool the chambers and affect carburation; as the chambers cool, she will want more fuel. Making steam take a huge amount of energy.
>Many times it happens that after you replace the fuel level sender and that little short jumper-hose, that you might have Not re-used the factory spring clamps. If you have used gear clamps, thinking they are better, that is a wrong thought. Gear clamps that small, have to be used in pairs, with the heads rotated about 180 degrees, so that the pump does not suck air from the gap that just using one clamp, creates.. That jumper needs 4 gear-clamps in total.
Good luck
Click to expand...


Thank you all for your suggestions. It's has stopped raining in Texas. Going to look at the suggestions. I will definitely look into the double hose Clos on the fuel sender. As far as the car. Is a 71 Duster. It started life a 6 cyl 3speed car. Put in 4 speed and a 340 which I am told was bored over. I did have someone on here who works on dragsters verify it. It has a 8.75 rear end previously from a 7.25. So it's basically a clone of a duster 340. It has drum manual brakes, manual steering No AC. Rpm intake with quick fuel carb which was purchase brand new. But it sat for a while during me traveling for work. I'll look into those suggestions. Any other help would be cool as well.
 
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