Hi,
I have a leak gas coming from the caburator . I even opened one side and cleaned the needle / washer with the spray cleaner. It helped stopping leak. When I tilted the machine it stopped leak completely. Can anyone help ?

Sounds like the float is set wrong or it is too heavy.

Hi,
My guess is you have a Tecumseh engine and you can obtain a free manual at:
Tecumseh Small Engine Specifications
And scrolling down to "L-Head Service Information" for the repair manual.
A manual for the rest of the machine may not be possible(impossible without model number) because part of the company became part of Homelite years ago and part remained with Textron. Mostly neither makes snowthrowers any longer.
I agree with the first answer, somewhat, and would see if the bottom of the float looks crushed; that would indicate the need for replacement.
Peace,
Clarke