Gas leaking out of a throttle shaft means the carburetor is flooding.
Flooding can be cause by any one of these things:
- Needle & seat leaking – to test see this page on how to test.
- Float is leaking – A Nitrophyl float must be weighed in grams. A brass float is tested by heating up a pan of water just prior to boiling, immersing the float and looking for bubbles.
- Float rubbing
- Float pin worn – inspect for groves.
- Power valve staying open