i think my qjet is defective

[ocbaud]

i had some new exhaust ran today to quite it down some(for me and my neighbors) i got dual magnaflows, with the exhaust dumped AFTER the axle. sounds nice and mellow at idle and screams when i get on it. it runs a lot better too. my dad took it to a performance shop in mustang, while i was at school, and they said that they couldnt time the engine correctly because the carb was so way off. they said it was idleing too high(which it has been). also, the idle mixture screws are messed up, they do not effect it at all. no matter how much i turn it in or out, i know i can drill the holes out, but, i shouldnt have too. the idle speed screw is also crossthreaded, it came that way when i got it, and it is so hard to turn it in and out. this weekend i'll be borrowing an 800cfm edelbrock eps carb to see how it runs, and possibly sending the qjet back. i've been thinking of getting one of those holley street avenger carbs.

[Destructo]

is it running very rich also? I had a holley once that was messed up and the idle screws couldn't be adjusted to work right at all, sent it back and got another one and the replacement one work fine. Adjusting the idle screws all the way in should kill the motor, if not then something is wrong.

[ocbaud]

it is running really rich. it smells like a lot of gas all the time. and i can turn the idle screws, both of them, all the way in and it will not kill the motor.

[LOHRTBT]

So if it was broken when you got it...tell me again why you didnt send it back immediately??

[ocbaud]

Originally posted by LOHRTBT
So if it was broken when you got it...tell me again why you didnt send it back immediately??

you know me, i'm not that smart


really though, i figured that it just wasnt tuned right and i could tinker with it to get it to work.

[MylilBowTie]

If its getting tooo much gas it will loose power. I would just try and get a replacement. If it still doesn't do what its supposed to then change to edelbrock or demon.

[ocbaud]

i was looking at those speed demon carbs. i've heard they are supposed to be pretty good.

[Captkaos]

If the meter screws are working, it make me think you have a vacuum leak. Partially cover the choke horn and see what happens.

Otherwise, I would send the carb back for replacement if you don't find an answer.

[ocbaud]

Originally posted by Captkaos
If the meter screws are working, it make me think you have a vacuum leak. Partially cover the choke horn and see what happens.

Otherwise, I would send the carb back for replacement if you don't find an answer.

putting a rag over the top of the carb didnt affect it. the idle mixture screws arent working either

[swervin ervin]

Well, if covering the air horn with your hand doesn't kill the engine, you have a vacuum leak. This would explain a high speed miss also.

[Captkaos]

Ditto, you have a LARGE vacuum leak hiding somewhere. That is why the mixture screws are ineffective. You can only control air going through the carb . I am surprised the place you took it didn't figure this out right off....

[PHOENIX]

One way to find the leak:
You can spray something flamable around the intake (or other places you think might be leaking) and the engine speed will change when you spray where the leak is. Carb cleaner works well.

[1FaastC10]

you could also have an internal vac leak inside the engine. usually happens on the lower part of the intake seals when it does happen.

[8t5Silverado]

Don't you have to disconnect some vacuum lines while adjusting the idle screws (or it doesn't do anything)?

[ocbaud]

Originally posted by PHOENIX
One way to find the leak:
You can spray something flamable around the intake (or other places you think might be leaking) and the engine speed will change when you spray where the leak is. Carb cleaner works well.

we sprayed wd40 all around the carb and adapter, and it didnt do anything to change the speed. i've checked back and forth for vacuum leaks, but i can't find any, anywhere

[swervin ervin]

Did you cap your hand over the air horn on the carb??

[ocbaud]

Originally posted by swervin ervin
Did you cap your hand over the air horn on the carb??

yea

[swervin ervin]

Well??? What happened???

[TwinTurbo]

I'm not getting this, it's running way rich and you want to drill out the idle mixture passages?? Try restricting them with some short sections of steel wire dropped into them. I've had plenty of carbs that needed to be leaned out like that to get idling correctly. (holleys especially tend to suck out of the box)

[swervin ervin]

Drilling out the idle discharge ports (idle mixture screw holes) does not make it richer. It gives it more air. You must remember the idle mixture screws control the amount of air not fuel.

[TwinTurbo]

oops... I have all lingo mixed up LOL

[ocbaud]

okay, i just went and tried covering the air horn on the carb. i put a rag over the top and it started to die. when i pulled it off, it revved up quickly and settled back down. so that means no vacuum leak, right?

[swervin ervin]

Right.