Carb Float chamber question

My B is running pretty rich and using alot of fuel, Ive made adjustments to the jets to lean up the mixture. I checked my float chamber levels, one chamber seemed to have way too much fuel in it, completely full to the brim.

In the Haynes manual it says its vital to get the right level in the chambers, it explains how you can adjust the float by bending its lever slightly, but looking at the illustration in the manual it looks like mine may be a more modern set of carbs as they dont seem to have anyway of adjusting the float,

Is there a way of doing it? They are standard SU carbs,

Also is this a big factor on how my car runs? Is that level vital to fuel consumption etc?

Any comments appreciated

Mark,

the manual refers to the very early B's only in this chapter, as they were still fitted with brass floats.
The plastic floats are not serviceable at that point and an exchage is needed if one of them starts sinking due to fuel getting inside it, altering the fuel level inside the fuel chamberl.
You might also check the float valves for equal hights and funktion.

Runnung on short distances only with a cold engine and many stop&go driving can show very bad mpg results too.

Ralph

Thanks Ralph, the haynes manual I have is from 1970, so I expected that to be the case.

The car is nearing completion so I havent been running it on the road, only starting it up every couple of days, but it seems to be using alot of fuel, even from me idling it for afew mins, I only ever put about 3 pounds of petrol in.

Ill check the float valves, worst case I suppose is that i have to replace the part, which isnt the worst thing in the world

The books were never edited to change instructions after the cars were changed.

Jimmie Hilton has/had floats for newer carbs that have brass tangs. Special order form England, as I recall. Whuich means if you look around you should find them since you are already there.

How to adjust the floats that do not have tangs.

First, I'd replace the needles and seats with new. The full bowl likely had a worn needle and let fuel in it should have shut off. Second, is the float cracked or leaking such that it won't, err, float? If so, replace.

The adjust float level with these non-adjustable floats I use thin nylon washers (about 30 thou thick, as thin as I can find) and place them under the seat as it screws into the float bowl lid. One is all I use.

Here's also my thought on what the level should be...since the book's instructions are clearly incorrect.

With the bell and piston out of the carb, and your eyebones looking down at the hole in the jet you will see fuel down there. The fuel level in the jet is the same as the level in the bowl as the two items are connected at the bottom by a hose. When fuel level is too high in the bowl, it is too high in the jet as well.

Take a piece of small plastic tubing and place one end on top of the jet so that when you blow into the tubing softly you are blowing into the top of the jet. give it a gentle puff and quickly remove the tubing at watch the fuel level in the jet. The puff will have pushed it down somewhat, but it will surge back up as it seeks to restore it's former level. If this surge brings it high enough that it floods over the top of the jet then the level in the bowl it too high. It should just come to the top of the jet, maybe a tiny bit of flooding, maybe not quite flooding. If this is what you see, the level is about right. if it floods, the level is too high. If it does not get close to the top of the jet, the level is too low. Fiddle with the washers to adjust further as needed.

I had a similar problem and it ended up being a defective jet assembly (which Chris Roop quickly replaced for me, thanks again). The defective assembly came straight from a Moss complete rebuild kit. I also agree with replacing the needle/seat and making sure your floats are good and are sitting at the correct measurements.

YOu can adjust the flaot level of the all palstic flaot with shims under the needle seat valve, Joe Curtoi has them, he can mail them in envelope, www.joecurto. As stated you can buy newer floats with the metal tang, but if your's are not taking gas and doing their job, it's as simple as a few shim, also may look into getter two new needle and seatr valve, often mismatching of these is what gets the float level off to begin with.