Electric Choke
3/21/14, 09:34 PM
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I have an electric choke. Should it be set to lean or rich? It runs perfect until operating temp then stalls and is Very hard to start up again.. 289 V8 . I also moved to flagstaff Arizona from Oregon. Sea Level to 7,000 feet.
3/21/14, 09:55 PM
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I have an '83 F150 with carb and electric choke. The indication it is set correctly is to be sure the throttle blade/butterfly is wide open once the engine is warm.
To adjust, I loosen the screws that allow me to twist the body of the choke to achieve the proper setting (round plastic body on back of carb connected to throttle blade and has an electric wire out of it). To do this I simply check it with the engine warm, and then twist the plastic body until it is wide open - no further - then tighten the screws.
When it is out of adjustment, the choke still closes the throttle blade after you set the choke on start up (key to on, depress gas pedal to set choke and let off*, then turn key all the way to start), but does not open completely on a warm engine (throttle blade is slanted) and therefore runs rich (really rough idle and some black smoke out the exhaust).
However, most carbs can only adjust from sea level up to 4000' feet or so. At 7000' (I assume Flagstaff), you may need to change main jets.
Also, if you flood a carb engine, floor the pedal and crank a few turns (this pumps the over-rich fuel mix out of the cylinders by letting a full charge of air in) and let it rest a few minutes. Then try to start as normal. Do not wear out your starter. Pause between attempts.
Another trick on carb engines when cold (assuming the main jet is correct and choke is set properly), is after 'setting the choke'*, pause a few seconds. This allows the fuel mist to atomize in the intake manifold (when you depress the pedal to set the choke you have also sprayed a mist of fuel into the carb throat via the accelerator pump). A well tuned engine typically fires right up like this.
To adjust, I loosen the screws that allow me to twist the body of the choke to achieve the proper setting (round plastic body on back of carb connected to throttle blade and has an electric wire out of it). To do this I simply check it with the engine warm, and then twist the plastic body until it is wide open - no further - then tighten the screws.
When it is out of adjustment, the choke still closes the throttle blade after you set the choke on start up (key to on, depress gas pedal to set choke and let off*, then turn key all the way to start), but does not open completely on a warm engine (throttle blade is slanted) and therefore runs rich (really rough idle and some black smoke out the exhaust).
However, most carbs can only adjust from sea level up to 4000' feet or so. At 7000' (I assume Flagstaff), you may need to change main jets.
Also, if you flood a carb engine, floor the pedal and crank a few turns (this pumps the over-rich fuel mix out of the cylinders by letting a full charge of air in) and let it rest a few minutes. Then try to start as normal. Do not wear out your starter. Pause between attempts.
Another trick on carb engines when cold (assuming the main jet is correct and choke is set properly), is after 'setting the choke'*, pause a few seconds. This allows the fuel mist to atomize in the intake manifold (when you depress the pedal to set the choke you have also sprayed a mist of fuel into the carb throat via the accelerator pump). A well tuned engine typically fires right up like this.
Last edited by cdynaco; 3/21/14 at 09:59 PM.
3/22/14, 12:05 AM
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I have an '83 F150 with carb and electric choke. The indication it is set correctly is to be sure the throttle blade/butterfly is wide open once the engine is warm. To adjust, I loosen the screws that allow me to twist the body of the choke to achieve the proper setting (round plastic body on back of carb connected to throttle blade and has an electric wire out of it). To do this I simply check it with the engine warm, and then twist the plastic body until it is wide open - no further - then tighten the screws. When it is out of adjustment, the choke still closes the throttle blade after you set the choke on start up (key to on, depress gas pedal to set choke and let off*, then turn key all the way to start), but does not open completely on a warm engine (throttle blade is slanted) and therefore runs rich (really rough idle and some black smoke out the exhaust). However, most carbs can only adjust from sea level up to 4000' feet or so. At 7000' (I assume Flagstaff), you may need to change main jets. Also, if you flood a carb engine, floor the pedal and crank a few turns (this pumps the over-rich fuel mix out of the cylinders by letting a full charge of air in) and let it rest a few minutes. Then try to start as normal. Do not wear out your starter. Pause between attempts. Another trick on carb engines when cold (assuming the main jet is correct and choke is set properly), is after 'setting the choke'*, pause a few seconds. This allows the fuel mist to atomize in the intake manifold (when you depress the pedal to set the choke you have also sprayed a mist of fuel into the carb throat via the accelerator pump). A well tuned engine typically fires right up like this.
3/22/14, 02:40 PM
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I have an '83 F150 with carb and electric choke. The indication it is set correctly is to be sure the throttle blade/butterfly is wide open once the engine is warm. To adjust, I loosen the screws that allow me to twist the body of the choke to achieve the proper setting (round plastic body on back of carb connected to throttle blade and has an electric wire out of it). To do this I simply check it with the engine warm, and then twist the plastic body until it is wide open - no further - then tighten the screws. When it is out of adjustment, the choke still closes the throttle blade after you set the choke on start up (key to on, depress gas pedal to set choke and let off*, then turn key all the way to start), but does not open completely on a warm engine (throttle blade is slanted) and therefore runs rich (really rough idle and some black smoke out the exhaust). However, most carbs can only adjust from sea level up to 4000' feet or so. At 7000' (I assume Flagstaff), you may need to change main jets. Also, if you flood a carb engine, floor the pedal and crank a few turns (this pumps the over-rich fuel mix out of the cylinders by letting a full charge of air in) and let it rest a few minutes. Then try to start as normal. Do not wear out your starter. Pause between attempts. Another trick on carb engines when cold (assuming the main jet is correct and choke is set properly), is after 'setting the choke'*, pause a few seconds. This allows the fuel mist to atomize in the intake manifold (when you depress the pedal to set the choke you have also sprayed a mist of fuel into the carb throat via the accelerator pump). A well tuned engine typically fires right up like this.
3/22/14, 05:24 PM
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Also, with it being choked down for a bit, time for an Italian tune-up and burn that carbon out!
3/22/14, 06:37 PM
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3/22/14, 10:13 PM
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