Automatic choke setting
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From: abilene kansas
Automatic choke setting
I have a question concerning adjusting the choke on my '80 F150. Which way do I rotate it for rich or lean. Do I turn it left or right?
Also, Which timing marks would I use to set base timing? I see some marks cast into the timing cover on the drivers side, and also a tab on the right side of the cover
Also, Which timing marks would I use to set base timing? I see some marks cast into the timing cover on the drivers side, and also a tab on the right side of the cover
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From: Northeast, OK
On the choke you usually rotate it clockwise to bring it on further, meaning make it richer. However, you can check that by doing the work on a cold engine. Note where the setting is, set the choke by depressing the throttle one time, hold the choke open lightly with your hand, and rotate the choke housing a bit. You should see and feel the choke go on or off further.
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From: abilene kansas
On the choke you usually rotate it clockwise to bring it on further, meaning make it richer. However, you can check that by doing the work on a cold engine. Note where the setting is, set the choke by depressing the throttle one time, hold the choke open lightly with your hand, and rotate the choke housing a bit. You should see and feel the choke go on or off further.
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From: Virginia
A lot of them have it written on the side in the plastic when it's molded. You might have to look carefully to see it. But then also, a lot of them have rivets and you are not supposed to adjust it. Those are easily drilled out and regular screws can be used. This is usually done when the carb is rebuilt.
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From: abilene kansas
A lot of them have it written on the side in the plastic when it's molded. You might have to look carefully to see it. But then also, a lot of them have rivets and you are not supposed to adjust it. Those are easily drilled out and regular screws can be used. This is usually done when the carb is rebuilt.
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From: Virginia
Just make sure you mark it before you move it. Then you can keep track of what's going on and which direction you moved it in. It will take several mornings to get it just the way you want it.
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You have a 300 six cylinder right?
Turning it to the trucks right, your left as facing the trucks windshield, will lean it out.
Turning it to the trucks left, your right as facing the trucks windshield, will richen it.
You should see the choke plate move, either closing or opening slightly. Remember to have these chokes close for cold starting, you have to press on the accelerator all the way to the floor to have it set or close. The fast idle cam will keep the choke open slightly, and the fast idle will not set unless you do so.
As for the timing marks, if your truck has the original factory harmonic balancer, then both can be used. The one on the trucks left, your right as facing the engine, etc... you have to line your eye up with the long TDC mark so your view runs down it's length. Sort of like it aiming straight at you etc. Then you can take readings off the other marks, so long as your eye is in line with the TDC's long mark.
The other mark is easier to use, because you don't have to line your eye up exactly to get a reading etc, but it's harder to get a good view at.
Be aware that newer replacement harmonic balancers do not have marks for both readings. The one on the tab is the default one etc...
Turning it to the trucks right, your left as facing the trucks windshield, will lean it out.
Turning it to the trucks left, your right as facing the trucks windshield, will richen it.
You should see the choke plate move, either closing or opening slightly. Remember to have these chokes close for cold starting, you have to press on the accelerator all the way to the floor to have it set or close. The fast idle cam will keep the choke open slightly, and the fast idle will not set unless you do so.
As for the timing marks, if your truck has the original factory harmonic balancer, then both can be used. The one on the trucks left, your right as facing the engine, etc... you have to line your eye up with the long TDC mark so your view runs down it's length. Sort of like it aiming straight at you etc. Then you can take readings off the other marks, so long as your eye is in line with the TDC's long mark.
The other mark is easier to use, because you don't have to line your eye up exactly to get a reading etc, but it's harder to get a good view at.
Be aware that newer replacement harmonic balancers do not have marks for both readings. The one on the tab is the default one etc...
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From: abilene kansas
You have a 300 six cylinder right?
Turning it to the trucks right, your left as facing the trucks windshield, will lean it out.
Turning it to the trucks left, your right as facing the trucks windshield, will richen it.
You should see the choke plate move, either closing or opening slightly. Remember to have these chokes close for cold starting, you have to press on the accelerator all the way to the floor to have it set or close. The fast idle cam will keep the choke open slightly, and the fast idle will not set unless you do so.
As for the timing marks, if your truck has the original factory harmonic balancer, then both can be used. The one on the trucks left, your right as facing the engine, etc... you have to line your eye up with the long TDC mark so your view runs down it's length. Sort of like it aiming straight at you etc. Then you can take readings off the other marks, so long as your eye is in line with the TDC's long mark.
The other mark is easier to use, because you don't have to line your eye up exactly to get a reading etc, but it's harder to get a good view at.
Be aware that newer replacement harmonic balancers do not have marks for both readings. The one on the tab is the default one etc...
Turning it to the trucks right, your left as facing the trucks windshield, will lean it out.
Turning it to the trucks left, your right as facing the trucks windshield, will richen it.
You should see the choke plate move, either closing or opening slightly. Remember to have these chokes close for cold starting, you have to press on the accelerator all the way to the floor to have it set or close. The fast idle cam will keep the choke open slightly, and the fast idle will not set unless you do so.
As for the timing marks, if your truck has the original factory harmonic balancer, then both can be used. The one on the trucks left, your right as facing the engine, etc... you have to line your eye up with the long TDC mark so your view runs down it's length. Sort of like it aiming straight at you etc. Then you can take readings off the other marks, so long as your eye is in line with the TDC's long mark.
The other mark is easier to use, because you don't have to line your eye up exactly to get a reading etc, but it's harder to get a good view at.
Be aware that newer replacement harmonic balancers do not have marks for both readings. The one on the tab is the default one etc...
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From: abilene kansas
I have noticed recently, sometimes I have to open the hood, open the throttle,and flick the fast idle cam up to close the choke plate. Is there something in the choke linkage binding, that I can free up?
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From: abilene kansas
It's a Carter YFA, electric with hot air tube. Is set to 2 rich as called for on emission decal
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From: Northeast, OK
Have you checked to see that the hot air tube is open so hot air can be pulled through? Many of those rot off and then only cold or cool air comes through.
And, have you checked to see that the electric choke has juice? IIRC those are connected to the alternator such that they get about 7 volts when the engine is running.
Also, does the carb have a vacuum pull-off? I don't remember if the YFA's do, but if so that is supposed to open the choke as the vacuum comes up.
And, have you checked to see that the electric choke has juice? IIRC those are connected to the alternator such that they get about 7 volts when the engine is running.
Also, does the carb have a vacuum pull-off? I don't remember if the YFA's do, but if so that is supposed to open the choke as the vacuum comes up.
Thread Starter
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Posting Guru
Joined: Dec 2012
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From: abilene kansas
Have you checked to see that the hot air tube is open so hot air can be pulled through? Many of those rot off and then only cold or cool air comes through.
And, have you checked to see that the electric choke has juice? IIRC those are connected to the alternator such that they get about 7 volts when the engine is running.
Also, does the carb have a vacuum pull-off? I don't remember if the YFA's do, but if so that is supposed to open the choke as the vacuum comes up.
And, have you checked to see that the electric choke has juice? IIRC those are connected to the alternator such that they get about 7 volts when the engine is running.
Also, does the carb have a vacuum pull-off? I don't remember if the YFA's do, but if so that is supposed to open the choke as the vacuum comes up.