float valve leak

[Ray White]

One niggle that I have lived with for many years is a leaking float valve (incorrectly called a needle valve) in the Zenith FZB carburettor.  The result (with which we are all familiar I am sure) is petrol dripping onto the exhaust.

I have attempted to cure this leak in the past but nothing seems to last for long. 

Has anyone found a solution?  If so I would like to hear from them.

Ray.

[Howard Wright]

Hi Ray

Willie McKenzie sells new needles and valves. I’ve had a set on my RK which seems to have lasted a fair time.

http://austinrepro.com/engine/

Cheers

Howard

[Colin Morgan]

I cured this with a later 26VA type carburettor by swapping to another float. Not sure why it worked, but it did.

[Dave Mann]

The first question I ask is the float level correct? When I get a 22FZB in for repair the first thing I do is to connect it up to a lawn mower petrol tank      with the throttle section removed so I can see the the fuel level in the main jet, I have to be quick because if the float valve is leaking you get a false high level. If the float valve is leaking both the needle and seat are removed and examined. If there is no obvious damage the needle is put in the chuck of my pillar drill with a drop of T cut on the business end and the seat is gently presented to the needle and the drill run at it's lowest speed. No great pressure is needed and the seat is regularly eased off the needle, I am only polishing the faces and they mustn't run dry.     This may take a couple of attempts and I never shut the fuel tap off even when garaged and they don't leak. Whilst I've used Willie McKenzie's needle valves and seats I've never had any success in making them seal and end up using the old seat.

[Ray White]

Thanks for the replies. I don't think my pillar drill is accurate enough (it's very old and basically clapped out) but I am tempted to give it a go...

Perhaps I could attempt to do the job on the lathe.???

Hmmm.