Quote:
Originally Posted by msinc
Yes sir, gold colored stains running down the intake manifold and making puddles....pretty much exactly as you say
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Here is what's happening: The engine runs nicely, gets nice and warm, you shut the engine off, the heat warms up the carb, the gas in the bowls starts to bubble up a bit, it percs up through and drips out the boosters, forming puddles on the butterflies, which drip down through the carb and over and out the side of the carb via the shafts, then down the outside of the carb leaving witness stains. The excess gas dripping out of the boosters on the hot day creates an overly rich flooding condition that makes it hard to start when hot.
Why is this happening? And why should I ignore the Holley tuning instructions? Three reasons: 1) Gas is not what it used to be; 2) The angle of your carburetor may be a contributing factor; and 3) the confined space of a Cobra's engine compartment creates additional heat load gain. A turkey pan helps, but it's not a cure-all.
Holley's tuning instructions of bringing your float bowl adjustments up to the bottom of the sight hole have not changed in 60+ years. When I first touched a Holley carb in the 1970's I could fill my tank up with Sunoco 260 that had the adjustable "dial-a-pump" that would deliver really great gas to you. Those days are long gone. Add to that the tilt of your engine/manifold/carb might be a contributing factor and you're left with one simple rule:
You can not simply set your float bowls to the bottom of the sight hole and forget it. You can only set them like that as the first step in your tuning process.
If I set my float levels to the bottom of the sight hole, and drive my car so it's nice and hot, then pull into the driveway and shut the engine off, if I remove the air cleaner a beautiful white puffy cloud will appear and form over the carb. On a completely calm day it's almost beautiful. And there's a small temptation to just lightly poke a lit cigarette into the cloud just to see what would happen. Don't do that. If you see the cloud, let the cloud dissipate by itself.
Look down the carburetor and see if you see droplets of gas on top of the butterflies on both the primary and/or secondary side. If you see puddles, or if you see drops coming out of the boosters, wait for the engine to cool and then loosen the set screw(s) for whatever side(s) were dripping and turn the float nuts clockwise by about a quarter turn in order to lower the float levels. Then on your next nice hot drive, repeat the process until you get the floats just low enough that you're not experiencing the booster drip problem. When the dripping problem is gone, try moving the floats up an eighth of a turn for extra tweaking.
Once you have the floats set properly you can tackle other aspects of setting up the Holley so it's just right. But a car that won't start after you've parked it hot is a huge PITA. Now, what you can do when it's like that is to put the accelerator to the floor and hold it there while you crank it. That will kind of clear the flooding condition out. Of course, you're giving it another squirt of gas when you do that so you make the condition a little worse before you make it better.
Anyway, that's how you fix it.
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