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Old 08-10-2020, 03:04 PM
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Cobra Make, Engine: ERA #732, 428FE (447 CID), TKO600, Solid Flat Tappet Cam, Tons of Aluminum
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Originally Posted by SBSerpent View Post
How did you realize your N&S were stuck? Was the car stumbling really bad? Smell of gas? Was it pouring through the boosters into the chambers?
Remember that any time fuel comes out of the boosters, when the butterflies are closed because you are idling, it will pool on top of the butterflies and then seep out through the throttle shaft and drip down on to the intake manifold. If you had a nickel for every post where some guy wrote "why is gas leaking out the side of my carb?" you'd be a millionaire. If it is on the secondary side on a vac secondary carb, it usually comes out the shaft and drips down off the plunger for the vacuum canister. If you look down the top of the carb while it is idling and you see little pools of gas on top of your butterflies then it means either your needle and seat is leaking or your floats are too high or the gas you are using is really $hitty and is percolating up and out through the boosters. A couple of years ago I did a full rebuild of my carb and set the floats dry on my bench. When I fired her up I set the floats to just at the base of the sight glass for both primary and secondary. Then I took her around the block three or four times and pulled her back in to the driveway (not the garage) and popped the hood and removed the air filter. Gas was dribbling out both primaries and secondaries at a pretty decent pace. I immediately shut her down and the prettiest white cloud formed about one foot over my carb that you have ever seen. If I had had a Lucky Strike in my hand I could have made a wonderful YouTube vid with it. In order for me to set my floats perfectly, so that I get no percolating after I shut her down on a hot day, I have to set the gas level about an eighth of an inch below the sight hole and the way I do it is by setting it just below the hole, then drive her, if she percs then set it a little lower, then repeat until both primary and secondary are set as high as possible without percolating out when hot.
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