It appears that the power valve in my Quadrajet has failed. Car coasts along fine but any sudden, hard acceleration (eg over-taking) causes immediate dead spot and it’ll immediately loose power and just roll along at idle until it recovers.
That said the model number on the Quadrajet reads 7045626. Looks like a 75 carby has been put on my 72. Having trouble identifying a rebuild kit for THIS EXACT carby
Or even just a power vale for now. HELP!
If you have ever had a Quadrajet apart, this might work for you. Rather than try to explain it myself, I found this
Many years ago I had a '68 Firebird with a Qjet. About once a year the power piston would stick in the down position.
I used a wire coat hanger with a ground down end and made a hook on it.
Just run it down the vent tube and hook the hanger, and give a little pull.
It will likely be a bit snug.
I then take a screw driver and push it back down. It will likely stick again.
Keep repeating the process until the piston can be pushed down and it will spring back up with no resistance.
After that, every few months, take a screw driver and bounce it a few times.
it shouldn't stick again.
Permanent fix is to remove the top of the carb and remove the piston and slightly hone the bore with very, very fine sandpaper.
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But if you don't know what the power piston looks like, might not be a good idea. Back when I took these apart all the time, this method saved me taking the top off the carb one time. My bible at the time was a Rochester Carburetor book by Doug Roe. In it he described how to make a 'key' shaped tool to go down the vent tube and free up the power piston. Worked perfect, but I think a perfectly bent coat hanger would work. Don't yank up too hard. Pull hard enough, you can pull the arm out of the piston. Like it says above. Give it a little pull. If it doesn't move, push it down a little. This method does work, but you have to have an idea what the hanger on the top of the power piston looks like. You could always take the top off the carb. That's how I learned. Trial and error. If you do it on the engine be REALLY careful with the 2 little screws down the primary bore and the one on the secondary needle arm. Drop one and you are then gonna learn how to take the intake manifold off. Q-jets used to be really plentiful. Actually in a pile at an auto wrecker. If you could get a spare to play with first, you would be an expert in no time. It isn't rocket surgery. A Rochester book helps but just to take the top off, free up the power piston and put it together, not really necessary. The top gasket can be reused. If you tap the pin out on the accelerator pump arm, remember to put something the width of a screwdriver against the intake horn so the pin will bottom out on it instead of the intake horn. Then you have the space you need to get behind it to pry it back in later. It's a huge PITA if you don't. Too bad you didn't live closer, I would pop over and show you how. It would take a wee drive to get to you.
Bic