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Registered
Join Date: Feb 2006
Location: Oahu
Posts: 2,303
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Foat height question
For all the carb experts out there. Can I set the float-height with the carbs on the bench, by hooking-up a gravity fed fuel supply? I'm trying to get as much done as I can, before putting them in the car.
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Jon |
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Join Date: May 2003
Posts: 3,346
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Hi Jon,
You could do that although it may change slightly when you use the 5 PSI from the pump in the car. I just do the measurements on the bench that the manual says and call it good. It involves measuring the depth of the float valve and the depth of the float tab with the float propped up to the measured height. I bend the tab on the float rather than changing washers on the valve. Hope you have some idea what I'm talking about. I don't have the numbers available as I borrowed the manual from a friend last time I did this. This procedure may be in the dreaded Haynes manual as well. -Andy
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72 Carrera RS replica, Spec 911 racer |
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Join Date: Jun 2004
Location: Rio Rancho, New Mexico
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As sensitive as Webers are to the correct float level, I would recommend the use of the external tube tool, which connects to the float bowl.
It's available from our host and it shows the float levels while running. Yes, it may take once or twice to get the floats just right, but it works. PMO's use a built in sight glass to check float levels. They knew what they were doing. Richard still know's what he is doing.
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DOUG '76 911S 2.7, webers, solex cams, JE pistons, '74 exhaust, 23 & 28 torsion bars, 930 calipers & rotors, Hoosiers on 8's & 9's. '85 911 Carrera, stock, just painted, Orient Red |
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Thanks Doug and Andy. I was going to use the float tool, and I thought about whether or not the fuel pressure would be a mitigating factor, but once the float rises and closes the valve, it seems that's it. I'm just trying to avoid doing it in the car, if possible. The last time, I had fuel everywhere, and it was a PITA. Andy, I'm going to have to get the manual. It would be interesting to compare the float height measurements with the site-glass tool. Up until now, I've been working with the set-up instructions from Richard and a few pages of info I got from a fellow Pelican. Thanks for the replys!
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Jon |
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Join Date: Jul 2000
Location: So. Calif.
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Jon,
I agree. You don't want the initial setting too high and risk flooding the engine with raw fuel. As I recall when I rebuilt my Webers years ago, I initially adjusted the float level using the Weber mechanical measuring jig that fits inside the float bowl. Once running, I used the external PMO sight glass and it was only off (low) by a washer. BTW, don't forget to safety-wire the float pivot pins. If one backs out (it'll conveniently do this 15 miles from home), you'll have no float effect... and no fuel shut off. FWIW, Sherwood |
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