Quadrajet intake gasket is wet, erratic high idle.

[MrSony]

Building a qjet for a guy, and it idles VERY high, at like 3.000 rpm. I managed to coax it down to 1400, but it refuses to go down anymore. Also, the base gasket that sits on the intake is wet every time I remove the carb. I have replaced the secondary plugs with the o ring plugs that quadrajetparts.com sells. They do not leak, nor do any of the other plugs that I can see. It also seeps fuel in between the main body and top surface of the throttle plate gasket and somewhere underneath enough to wet the base gasket. What is going on here? Is this carb just junk? It's a 17057204 off of a 78 corvette with a stock 350. And to be fair, the engine I'm testing it on is an 81 305, but it's all I got to work with. I've built maybe 20 qjets so far, and I've never had one as troublesome as this one. Any help is appreciated.

 

[MrSony]

Also is the process for setting the fast idle what I remember it to be? Starting with a stone cold motor, back both idle screws out (fast and curb), crack the throttle open a tad, turn in the fast idle screw, and get it to idle where you want it, wait until its at temp, then adjust the curb idle. IS that right?

 

[pontiacgp]

if you have built 20 quadrajets we should be asking you questions. What is the float set at?

 

[pagrunt]

Have you doubled checked the base & body for cracks?

 

[TURNA]

The rebuild kits use to come with a thick gasket to go between the bowl and base plate to correct this problem.

 

[Texas82GP]

Diatortion between the base and body? Allowing unmetered fuel into the intake?

 

[TURNA]

Sounds like the thingamajig isn't seated properly to the whatchamacallit.

Resulting in the gizmo to to have leakage from the doodad.

Once that is fixed the doohickey should properly line up with the thingamabob resulting in proper function of the petroleum air mixer maximizer.

Let us know how it works out.

 

[olds307 and 403]

It sounds like a float level issue or possibly too high of fuel pressure. Did you replace the float? Who's kit did you use? I have built a few as well and had weird issues as well I never solved, used have a bunch of spares so I just swapped it out. I sent my last one for a custom tune since it ran terrible after cleaning and reassembly, never ran a high compression Olds 350 before.

 

[pontiacgp]

I have built a few quadrajets and I always reference my Cliff Ruggles book, the float level, adjustments for the choke and throttle are by way of measurements and not guesswork.....and once the carb is built I have my Air/Fuel mixture gauge to tweak it. I have seen "junk" quadrajets that run great once they are properly built and adjusted.

 

[SSpev]

Will it idle with the mixture screws closed? gas leak or throttle open to much. Throttle should only uncover the transfer slot about 1/16 of an inch.
are the primary rods in right? get swapped? is the secondary cracked open? did you check flatness between the base and bowl - bowl and top?
And the real kicker on a q jet. Did you check the throttle shafts for wear? There is almost always to much wear. I ALWAYS drill and bush the shafts.