Crypton synchro check model B89 carb balancer

[Cylo7]

Hy all,
Does any member have or can provide a copy of the user instructions for this device.
The main question I haves is not how to use this but what is the black pull out button for ????

Thanks
Ian

[GDPR]

Changes the scale between high and low airflow in the case where you are trying to balance carbs on a tiny little set fitted to an A series, and then a 6+ litre engine such as a Rolls Royce

[Cylo7]

Thanks,
That makes a lot of sense at first I thought it might just be to lock the pointer so you could remove it then read it, but that did not work.
Many thanks for solving my question

Regard
Ian

[GDPR]

No problem. Wish I still had mine, but some thieving little scrotum broke into my toolbox at work in '95 when I was on holiday and "borrowed" it.

Had my suspicions who the light fingered pond scum was but couldn't prove and Crypton had stopped making them so couldn't replace it.

Then the advent of eBay brings secondhand ones onto the market at several times their new price - maybe I'll buy another if the right price comes up...

I'm not bitter about it.....really..... honest....

Russ