Author Topic: FLOAT LEVELS  (Read 334 times)

Offline qjetsrule

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FLOAT LEVELS
« on: September 10, 2019, 09:42:54 PM »
Why are there so many float level settings for a qjet when you get a generic rebuild kit. Was it really that critical for each engine?

Offline Cliff Ruggles

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Re: FLOAT LEVELS
« Reply #1 on: September 11, 2019, 02:19:10 AM »
The factory used a lot of higher pressure fuel pumps in later years and many set-ups had returns systems as well.  This was done with most A/C equipped cars and they also thought that circulating the fuel would help keep it cooler.

You'll see a lot of carbs with very low float settings.  I only follow those guidelines if the carb is being used on the original stock application and still has the stock fuel pump (rare).......Cliff

Offline 77cruiser

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Re: FLOAT LEVELS
« Reply #2 on: September 12, 2019, 05:57:05 AM »
I've been using 1/4 - 9/32 with 6 -6.5 lbs. fuel pressure, seems to work OK.
Jim

Offline Cliff Ruggles

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Re: FLOAT LEVELS
« Reply #3 on: September 13, 2019, 05:39:07 AM »
I use 9/32" and 7.5 PSI from a 140gph electric pump with a return.

Been flawless for nearly 20 years, with 5 wins at the Pontiac Tri Power Nat's at Norwalk and two trips to the "King of the Hill" race....I guess it's not a bad place to be with a later carb.

I would note that a couple of customers have noted issues with hard braking when the plastic filler cup is left out of the later models.

I've not seen this with my car and I've been on the brakes pretty hard a few time at the track over 120mph to make sure I crossed the line first w/o running under my dial in. 

Did some hard braking on the street as well and zero issues, but we have been leaving the filler cup in builds anyhow, just to avoid a potential issue in that area........Cliff

Offline Kenth

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Re: FLOAT LEVELS
« Reply #4 on: September 14, 2019, 11:55:15 AM »
I have found that the float settings corresponds with the size, length and diameter, of the main discharge nozzles as they are different for each division Quadrajets.
Some models have nozzles sitting further out for sooner start of fuel delivery.
A long, larger diameter nozzle that sits out in the booster will require lower float settings and may use "leaner" primary rods.

Offline qjetsrule

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Re: FLOAT LEVELS
« Reply #5 on: September 20, 2019, 10:01:12 PM »
interesting observation, I didn't know you could remove the nozzle without destroying the casting