BAD POWER VALVE?
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Freshman User
Joined: Jul 2014
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BAD POWER VALVE?
My 72 f250 with a motorcraft 2barrel does not want to accelerate and it dies if I accelerate quick. But keeps up when I accelerate slow. It struggles to move under weight. It is also flooding, I cleaned the needle and the cylinder but did not help. Also when I move the air screw on the right side it doesn't make a difference. My new diaphragm is starting to leak a lil. Should I just rebuild the carb?
Hotshot
Joined: Mar 2013
Posts: 14,255
Likes: 199
From: Phoenix, Az.
2X Rasputin. It'll have real gaskets in it rather than glorified cardboard. Ford part number D4AZ9A586A. Autolite 2V's are simple carbs. Just watch the little things. Like the Spring wire retainer that holds the float pin in place and where the check ball goes under the venturi assembly. These carbs have a cool aspect to 'em. You can take the lid off of them while the engine is idling. I'm not suggesting doing it but it's possible. 
Lead Driver
Joined: Jan 2003
Posts: 9,893
Likes: 12
From: Ohio
If it stumbles/dies when you hit the throttle, it is the accelpump. Either the pump or the linkage> Typically I have always had issues with the linkage. The spring on the throttle shaft that pushes the linkage always gets gummed up and doesn't work smoothly/quick enough. Thus giving you a hesitation.
There is NOTHING to these carbs. Very simple.
Are both mixture screws out the same amount? (around 1 1/2-2 turns out) If not, it might not make one work well/at all due to being too rich on one side. Or could just be gunked up passage.
There is NOTHING to these carbs. Very simple.
Are both mixture screws out the same amount? (around 1 1/2-2 turns out) If not, it might not make one work well/at all due to being too rich on one side. Or could just be gunked up passage.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 785
From: Simi Valley, CA
D4AZ-9A586-A (replaced C2AZ-9A586-B) .. 2100 series Auto-Lite/Motorcraft 2V Carburetor Kit (Motorcraft CT-499-D) / Available from Ford and auto parts stores.
Applications: 1962/74 Passenger Cars/F100/350's - 1966/74 Bronco's - 1969/74 Econolines.
Kit includes the gaskets, accelerator pump, accelerator pump check valve, power valve and etc., but does not include the choke pull-off diaphragm used on 1970/74's.
D0AZ-9J549-C .. Choke Pull-Off Diaphragm - located on top of air horn (Motorcraft CM-1283) / Obsolete - Available from auto parts stores.
Applications: 1962/74 Passenger Cars/F100/350's - 1966/74 Bronco's - 1969/74 Econolines.
Kit includes the gaskets, accelerator pump, accelerator pump check valve, power valve and etc., but does not include the choke pull-off diaphragm used on 1970/74's.
D0AZ-9J549-C .. Choke Pull-Off Diaphragm - located on top of air horn (Motorcraft CM-1283) / Obsolete - Available from auto parts stores.
Lead Driver
Joined: Aug 2003
Posts: 7,592
Likes: 10
From: **** hole San Jose ca.
Yup sounds like the power valve, if you can close the air/fuel screw all the way in and it will not kill/stall the engine. This shuts off the gas completely with a good power valve.
But with a bad power valve gas gets sucked through it an the engine will keep running.
Orich
But with a bad power valve gas gets sucked through it an the engine will keep running.
Orich
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quakerj
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
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Nov 12, 2014 04:02 PM
