Carb Question
Thread Starter
Pro
Joined: Jul 2000
Posts: 590
Likes: 1
From: Suffolk New York
Carb Question
I rebuilt a Holley Carb, Probably didn't do a good job. Seems to be dripping gas rather than a fine mist. It doesn't idle well. I've plugged all the Vacuum hose to see if it was a leak.
The cam in the car is a solid lifter flat tappet, pretty big I assume since I only get like 5in of vacuum.
The power valve I used came with the rebuild kit, but I think I need a different one because of my cam any one else agree?
If I were to get a new carb, any suggestions?
The cam in the car is a solid lifter flat tappet, pretty big I assume since I only get like 5in of vacuum.
The power valve I used came with the rebuild kit, but I think I need a different one because of my cam any one else agree?
If I were to get a new carb, any suggestions?
Melting Slicks
Joined: Oct 2008
Posts: 2,154
Likes: 69
From: Regina Sk Canada
Well if you are only making 5 " of vac, check to see that you have a 2.5 power valve in it. What does is make for vac in gear? You need to be 2 sizes smaller on the power valve than the vac reading in drive.
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
At what rpm point is it dripping gas? If you're witnessing this at idle and it's coming from your boosters, then your fuel level in the bowls is too high. If it's at higher engine speed, it could be any number of ills in your main emulsion well, but this would be pretty hard to see while eyeballing the boosters since the main circuit has to be flowing. This would be a fuel shear issue. Outside of more detail, I'd have to guess it's an idle and fuel level issue since the boosters don't have enough velocity to shear fuel and this is when you'll get the big drops instead of the atomized delivery.
If this is at idle, it won't be in your power valve since this circuit flows fuel only when the boosters are flowing and it would be the same fuel shear problem.
If this is at idle, it won't be in your power valve since this circuit flows fuel only when the boosters are flowing and it would be the same fuel shear problem.
Thread Starter
Pro
Joined: Jul 2000
Posts: 590
Likes: 1
From: Suffolk New York
Thread Starter
Pro
Joined: Jul 2000
Posts: 590
Likes: 1
From: Suffolk New York
At what rpm point is it dripping gas? If you're witnessing this at idle and it's coming from your boosters, then your fuel level in the bowls is too high. If it's at higher engine speed, it could be any number of ills in your main emulsion well, but this would be pretty hard to see while eyeballing the boosters since the main circuit has to be flowing. This would be a fuel shear issue. Outside of more detail, I'd have to guess it's an idle and fuel level issue since the boosters don't have enough velocity to shear fuel and this is when you'll get the big drops instead of the atomized delivery.
If this is at idle, it won't be in your power valve since this circuit flows fuel only when the boosters are flowing and it would be the same fuel shear problem.
If this is at idle, it won't be in your power valve since this circuit flows fuel only when the boosters are flowing and it would be the same fuel shear problem.
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
Try harder. The only cause of fuel coming out of the boosters at idle is the fuel level in the bowls is too high. It could be the floats are set too high, bad needle and seat, fuel pressure too high, or a faulty float.
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
At what rpm point is it dripping gas? If you're witnessing this at idle and it's coming from your boosters, then your fuel level in the bowls is too high. If it's at higher engine speed, it could be any number of ills in your main emulsion well, but this would be pretty hard to see while eyeballing the boosters since the main circuit has to be flowing. This would be a fuel shear issue. Outside of more detail, I'd have to guess it's an idle and fuel level issue since the boosters don't have enough velocity to shear fuel and this is when you'll get the big drops instead of the atomized delivery.
If this is at idle, it won't be in your power valve since this circuit flows fuel only when the boosters are flowing and it would be the same fuel shear problem.
If this is at idle, it won't be in your power valve since this circuit flows fuel only when the boosters are flowing and it would be the same fuel shear problem.
It's a common misconception that the power valve has any affect on the idle mixture - it affects the mixture only when the main circuit is started, and then its effect is to provide a enrichment when the vacuum drops below its nominal value. At idle, there should be NO fuel coming from the boosters.
Race Director
Joined: Oct 2000
Posts: 15,044
Likes: 79
From: central FL, near the beach.
But with this big cam, and 5", he may of turned the idle screw speed in so far that he is idling on the main booster
unlikely, true, but you never know 
until u look
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Race Director
Joined: Oct 2000
Posts: 15,044
Likes: 79
From: central FL, near the beach.
switch f & r needle. if rear floods, there is dirt on needle.
PV is important, but not today. 1st set fuel level, stop drip.