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Old 06-25-2013, 03:04 AM   #1
jnealg
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Default Qjet adjustments?

so I am wasting time at work on the night shift and thinking about the 75 that will reapply the smile on my face on the drive home...



When warm it runs fine, no issues with performance other than its a L48.

1> When cold and I set the choke, it has to warm up in order to not bog down when I let the clutch out. I have to give it more gas than I feel I should and let the clutch out slowly or it will die.

I think the answer is to adjust the choke dial and richen it up a bit. Correct? It just seems like I need a bit more fuel.

edit: choke seems to function properly and seems to be aligned properly when set.


2> I know I want to go in and adj the A/F needles at some point just to make sure it is good. I plan on doing it with a mity vac as it is the only vac gauge I have. I need to use a manifold port correct? would the port directly on the intake be appropriate such as where the vac comes for the lights, or do I need to actually pull it off the carb?
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J. Neal Goggins

1975 l48 Silver Convertible 4 spd
1999 light pewter convertible auto
1969 red convertible 4 spd (basket case)


Previously:
1996 Lt1 Black coupe

Last edited by jnealg; 06-25-2013 at 03:19 AM.
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Old 06-25-2013, 03:06 AM   #2
oldalaskaman
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member Lars is the resident qjet man , look for his papers and threads on here
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Old 06-25-2013, 03:17 AM   #3
jnealg
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yeah at some point I am going to contact him to do a rebuild. maybe over the winter.

tnx
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Old 06-25-2013, 03:43 AM   #4
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his tech sheets are pretty detailed, may just need to adjust
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Old 06-25-2013, 04:26 AM   #5
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Default

Lars Q-Jet papers will establish a great baseline for adjusting your choke. Everyone I've set up using his papers has been thrilled with the choke performance.

Question 2; by A/F needles do you mean idle mixture screws or the metering rods? The idle mixture screws you'll have to get samples from a few ports, esp with a dual plane. The screws only affect one side of the engine and a single port won't give you the complete picture. Actually, the power brake booster port bleeds from the center of the carb and is probably a better bet than the manifold fitting (which reads off the right hand port if I'm remembering right).

For the metering rod adjustment, any port is fine although I would probably tune that circuit by feel or by lambda (AFR) gauge.

Last edited by Shark Racer; 06-25-2013 at 04:29 AM.
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Old 06-25-2013, 06:40 AM   #6
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Thanks and yes I meant the idle mixture screws.
I sent Lars an email requesting his papers.

I dont think I really need a rebuild although I doubt it's ever had one. We will see where I end up after adjustment.
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Old 06-25-2013, 06:40 AM
 
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