How to adjust a float?

Topic: How to adjust a float? (Read 930 times) previous topic - next topic

How to adjust a float?

October 10, 2006, 10:30:19 PM

I would've thought the answer to this would be written in the manual but no. To adjust a float on my Holley you have to turn the adjusting nut counterclockwise to raise the float and clockwise to lower it. That's all well and good. But what does raising it or lowering it actually accomplish in terms of fuel level? I just spent the better part of an hour leaning over the engine turning that nut this way and that with no noticeable difference in fuel level, it's nowhere close to the level of the sight plug. It's entirely possible the float is frozen and I wasn't accomplishing anything but let's assume it's not. Should I be trying to raise or lower the float?

How to adjust a float?

Reply #1 – October 10, 2006, 11:38:24 PM

http://www.xs11.com/tips/maintenance/maint20.shtml

GOAL:
Accurate and sufficient fuel level in the float bowl

Too low fuel and the bowl may run dry under full throttle
Too high and carburetors may leak fuel through overflo under conditions of sudden flow change.

How to adjust a float?

Reply #2 – October 11, 2006, 08:12:41 AM

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To adjust a float on my Holley you have to turn the adjusting nut counterclockwise to raise the float and clockwise to lower it.

Technically, you're not moving the float... you're moving the inlet valve assembly, which the float arm presses against. Raise the inlet, the float (and the fuel level) must be higher to shut off the flow. Lower the inlet, and a lower fuel level will do it.

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I just spent the better part of an hour leaning over the engine turning that nut this way and that with no noticeable difference in fuel level,

With the engine running, to let the fuel bowl be (slowly) refilled or emptied, as the case may be? It may take a minute to stabilize.

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It's entirely possible the float is frozen

Then either the bowl would never fill, or it would keep filling until it overflowed, since the float wouldn't be controlling the inlet valve.

How to adjust a float?

Reply #3 – October 12, 2006, 10:45:32 PM

Okay now I know why the car wouldn't start cold. The last owner of this carb COMPLETELY backed off the fast idle screw. I'm guessing it's something to do with this carb being off a racing engine but I couldn't really say. As for the float the other night I turned and turned and turned it til it started to resist me a bit and I figured I better leave it alone. But the fuel level stayed more or less where it was, refusing to come up to the sight plug. I'm running a Holley 110 gph pump but I'm still using 5/16 line. Any chance that's the problem?