Marvel float.

Unknown

Okay, here is the text I tried to post, see if it
comes out this time!

Geoff.

 

 

First of all, the air valve is simply a flapper
that covers the main jet, and progressively opens as the throttle is opened,
allowing more air flow past the jet nozzle.  It could probably have been
mechanically operated, but that is how it is!  Regarding the cork float, it
would probably be best to make a new one out of block cork (should be available
from hobby shop/craft shops) and paint it with polyurethane paint.  Don't
use tank sealer, it would be too heavy methinks.   For the needle
valve, I take the needle out and mount it in a drill press and run it against a
very fine stone at high speed to re-shape it to a straight shape again. 
Then lap it in using silver polish in the seat. To set the float level properly
you need to remove the carburettor, measure the distance from the top of the
float bowl to the top of the low speed jet, and then connect to a gas supply,
and measure the distance to the top of the fuel, which should be 1/8" below the
jet.