Qjet Float Height Looks Wrong

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pontiacgp

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Mar 31, 2006
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I just like the idea of the on off switch with the rod as opposed to the progressive ones that I have. Seems I'll never know how far down the thing is unless there's a way to apply vacuum on the bench?

mytivac can do the job for the vacuum....for the the stepped rods for 76 and up are stamped K and I think P but check the lenght. The pre 75 are .080 longer
 
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Bonnewagon

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The only way I know is to cut a carb in half so you could see. I am not sure if the rod hangers interchange. You would have to eyeball them side by side. The tapered rods always felt better to me. Smooth transision.
 
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Supercharged111

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The only way I know is to cut a carb in half so you could see. I am not sure if the rod hangers interchange. You would have to eyeball them side by side. The tapered rods always felt better to me. Smooth transision.

Based on the manual I'm reading I'm having a tough time visualizing how to measure for the APT with the tapered screws. I agree they are better in principle, just more difficult to get right. I may well just need more time to process this as the qjet is ridiculously tunable and adaptable. It doesn't get any closer to EFI than this.
 
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pontiacgp

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If you are not sure the adjustment of the APT was at in your carb like Mark suggested start off at 4 turns. Before you put the horn back on puch out the plug so you can adjust the APT screw after the horn is installed. I'm cheap so I drilled a small hole in the plug so I could put the plug back in after adjustment and I could use a small screw to pull the plug out if needed. To adjust the APT I used a piece of 3/16" brake line and formed one end to fit over the APT head and bent the other end 90° so I could gauge how much I adjusted the APT. You can buy a threaded plug and APT tool online if you're not cheap like me... :popcorn:
 
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Bonnewagon

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The APT is also a Double D just like the idle screws. So the 1/4" DD socket fits. But a cheapola like me can also use the secondary hanger with the end ground off. It is just long enough to turn the APT screw. In all the carbs I have taken apart the APT was always between 3.5 and 4.5 turns. Thus 4 turns is a good ballpark adjustment.
 
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Supercharged111

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Hmm, mine was just over 2 1/4 turns, wouldn't that be super lean? I'll just send it for now with that mental note. Car was anything but lean before. My double D bit wouldn't touch the APT so I dremelled out a screw and attached it to video grips. Paint marker was a bit dry but served it's purpose. Also pictured it the cover screw thingy, I staked the plug into it and ground a flathead ridge into it.

IMG_20200906_191114.jpg


And yes, the screw fits through the airhorn.
 

Supercharged111

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Just did the common sense thing and shined a light down there. Looks close to me.

IMG_20200906_193116.jpg


I wonder if the tapered rods just need the screw down farther? I backed it out 1.5 more turns and the rod is not all the way in the hole. Not sure if the pic shows that well.

IMG_20200906_193510.jpg


After this, I went and put it back so the pin would hit the witness mark on the APT screw. That comes out to a nice 2.5 turns instead of no man's land. I probably fiddled with it last December and forgot.
 

Supercharged111

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Oct 25, 2019
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Next question: I didn't know there was a check ball down here until I was watching a YouTube video on putting this thing back together. What does it do? It's acting like it doesn't want to come out so I have some carb cleaner in it for the time being.

IMG_20200906_194421.jpg
 
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