Choke pull down not working!
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Choke pull down not working!
I just got a 78 Ford supercab with the 351M and although it runs okay it idles too high and the plugs show that this has been happening for a while. I can manually flip the choke down and it purrs like a kitten. Can anyone tell me the proper order/way to troubleshoot this to determine the cause. The carburator was covered in varnish and I sprayed it down well with carb cleaner but I don't know if that is what is causing this problem or not. I know I need to rebuild the carb most likely but for now I would just like to get this working so I can tune it up a bit. I plan on getting all of the body work done before I start on the engine stuff. Once this is solved that is!
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From: chicago burbs
i've heard of a choke "pull-off" but i don't know what a "pull down" would be? the "pull-off" is vacuum operated and it opens the choke the initial 1/4" or so for start up.
"Electric chokes use 12v current to warm up a thermostatic spring(bi-metal coil) and open the choke after cold start-up." some are not 12v but work the same way with less voltage
if yours is an electric choke it sounds like this is not happening. it could be as easy as adjusting the bi-metal coil housing to the "lean" direction, but the bi-metal coil might be bad or it is not getting voltage?
"Electric chokes use 12v current to warm up a thermostatic spring(bi-metal coil) and open the choke after cold start-up." some are not 12v but work the same way with less voltage
if yours is an electric choke it sounds like this is not happening. it could be as easy as adjusting the bi-metal coil housing to the "lean" direction, but the bi-metal coil might be bad or it is not getting voltage?
Last edited by grclark351; Feb 17, 2006 at 08:56 PM.
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I just looked at it and there are NO wires going to it. Only a vaccum from the intake. It does say lean on it with an arrow for direction to turn but it appears to be riveted on with no way to adjust. I have a feeling there is a vaccum leak because the transmission shifts hard and the modulator valve on the C6 transmission is vaccum assisted from the intake to smooth shifting. I started checking vacuum lines and one of the little plastic elbows broke. Now I need to get replacements. I also found two vaccum hoses that are plugged off with screws. Where could I get a complete vaccum diagram for a 78 351M? The original label is not under the hood. Thanks!
Ty
Ty
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Does anyone know what this is or what it does? The one port (middle) that is broke is what I did by accident this morning but what about the third port that has nothing attached?
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From: The Big, Oregon
To adjust the choke, loosen the three screws around the cap, and turn it. Make sure the tube going to the intake is intact, it actually draws air from the carb top inside the intake, through a coil in the exhaust passage in the intake, and then up through the choke to heat the element. I believe there also should be a heater hose running by the choke housing to keep it warm while the engine is warm and assist with the choke opening.
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From: East Texas
The last picture you posted is the vacuum amplifier. I have no idea where you might find one. You might try the local Ford parts department. Otherwise it's a wrecking yard trip. One of the vacuum hoses from the amplifier (probably from the broken part) should be routed to the vacuum reservoir (coffee can) on the passenger side front of engine compartment by the battery.
Last edited by firstonraceday; Feb 18, 2006 at 09:36 PM.
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I thought this was a vacuum problem so I removed all of the emissions stuff and plugged all of the extra ports. It turned out I just had to adjust the choke and idle. Some fool had turned it way up. Who knew? Thanks for everyones help!
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