Qjet question
Race Director
Joined: Jun 2000
Posts: 10,053
Likes: 679
From: FL
Re: Qjet question (clem zahrobsky)
I do not agree with the standing wave of fuel theory. My opinion is that your float level is probably set too high thereby causing an overflow condition.
Time to get Lars' opinion.
Time to get Lars' opinion.
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Qjet question (SteveG75)
it is called reversion and if you ever watched a dyno run you will see it. fuel vapor just hangs above the carb. they even make anti reversion plates for some race applications. it will richen up the mixture as extra fuel gets pulled back throught the carb the second time :chevy
[Modified by clem zahrobsky, 5:23 PM 10/31/2001]
[Modified by clem zahrobsky, 5:23 PM 10/31/2001]
Le Mans Master
Joined: Jul 1999
Posts: 9,206
Likes: 17
From: Sewell NJ
Re: Qjet question (FERL 73)
I'm not sure if this is the answer but I'll tell you what happened to me. I had a problem with gas smell for a long time and finally tracked it down. I've been using a drop base 14" chrome air cleaner. For some reason the car always smelled of gas after I drove it. I replaced the air cleaner recently and installed a 1" riser around the carb neck to raise the air cleaner. Problem is gone. The only thing I can think of is that the lid of the air cleaner may have been pulling fuel out of the reservoir or causing a reversion problem because it was too close to the air horn. All I know is that it doesn't happen anymore and I still have enough hood clearance.
Tech Contributor
Joined: Aug 1999
Posts: 14,384
Likes: 6,411
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Qjet question (vettfixr)
Hi guys!
Clem is right. The Q-Jet is a pretty sloppy carb at WOT. Fuel literally sprays everywhere out of those secondary discharge tubes, and you get a "cloud" of fuel above the secondary airvalve. There will be raw fuel on top of the airvalves and splashed into the cavity indicated. Believe it or not, but this is actually normal operating procedure for a Q-Jet.
If your float level is too high and causing a fuel leak problem, you will normally have fuel leaking up past the accel pump rod and settling into the recess around the pump rod. If this area stays reasonably dry under normal driving and at idle, your float level and fuel control is okay.
[Modified by lars, 12:34 PM 10/31/2001]
Clem is right. The Q-Jet is a pretty sloppy carb at WOT. Fuel literally sprays everywhere out of those secondary discharge tubes, and you get a "cloud" of fuel above the secondary airvalve. There will be raw fuel on top of the airvalves and splashed into the cavity indicated. Believe it or not, but this is actually normal operating procedure for a Q-Jet.
If your float level is too high and causing a fuel leak problem, you will normally have fuel leaking up past the accel pump rod and settling into the recess around the pump rod. If this area stays reasonably dry under normal driving and at idle, your float level and fuel control is okay.
[Modified by lars, 12:34 PM 10/31/2001]
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