A common complaint.
The outlet tube on most filters goes nearly all the way to the end of the filte tat you can see.
In a lot of them this ube has only 1 hole at the very end.
So there is an air pocket at the outlet end of the filter.
This looks worse if the filter is vertical, outlet side up.
Over time it will eventually fill up but it is not uncommon to find one 2 years old still only 1/2 full.
If you fit it inlet side up or flat it will fill better.
Have you tried to start it? If so and nothing happens, try loosening/removing the tank cap and /or prime the carb either w/ your primer bulb or a little gas in the carb. That should start the engine and start pulling the fuel through.
