Zenith 22 FZB Carburettor

[cwchrisp]

Good Morning,
Quick question regarding the 22 FZB Mazak carb. please.
Where the top section joins the bottom at the slow running jet interface, is there a fibre washer, a metal washer or left open to allow air into the slow runnng jet?
On the 22 FZ, there is a flap covering air holes, so my guess is the gap is left open on the 22 FZB?
Many thanks.
Chris

[Dave Mann]

    There is no joint between the top and bottom of a 22 FZB carburettor, that's where the air gets in. Take no notice of the hole, that's for the screw to retain the new slow running jet housing.

[cwchrisp]

Perfect, thanks so much.
I am trying to patch up the cracked aluminium, I wish I had your machining skills!
Chris

[Dave Mann]

    I had one like this on the back of my bench for years until I found a length of 14 mm OD x 10 mm Id drawn steel tube at work then the repair procedure became obvious. There are two causes of this;
1) The mazak must be 100% pure otherwise it gradually disintegrates as Meccano found with their Dinky toys
2) Previous owners loose the slow running jet retaining screw and fit an over length replacement which is over tightened jacking the side of the housing off.
I've run out of the 14mm x 10 mm tube and haven't found a supplier who wants to sell me anything less than 20'

[Tony Griffiths]

I had one like this on the back of my bench for years until I found a length of 14 mm OD x 10 mm Id drawn steel tube at work then the repair procedure became obvious. There are two causes of this;
1) The mazak must be 100% pure otherwise it gradually disintegrates as Meccano found with their Dinky toys
2) Previous owners loose the slow running jet retaining screw and fit an over length replacement which is over tightened jacking the side of the housing off.
I've run out of the 14mm x 10 mm tube and haven't found a supplier who wants to sell me anything less than 20'

Any good?
https://www.ebay.co.uk/c/9004859742

https://www.ebay.co.uk/itm/14MM-OD-X-10M...2458066256

..and stock item 363841 https://www.pipestock.com/steel-tube

[cwchrisp]

[attachment=10208]

I have a 'lockdown' project to build an FZB from bits I had and some from ebay.
The top section had the same problem around the slow running tube and I used J-B Weld to patch up.
I removed my FZ today and tried out the FZB and apart from the the float bowl needle seat bebing the wrong type, it seemed to work!!
I had to manually top up the float bowl using the petrol tap to maintain engine running...what fun!
Apologies for any errors posting as I am very new to this forum!!

[Dave Mann]

Thank you Tony.