B&S V-Twin carburetor repair

I have carburetor "issues" on my B&S V-Twin 12 HP generator engine. The engine has less than 20 hours on it... so I'm convinced it doesn't need a rebuild kit.
I'm sure that the gas in the tank had gotten very old, so I've tried cleaning the carburetor, but it still doesn't work.
There is a needle valve on the outside that is covered with a plastic cap that I can't remove. I think this is the culprit.
Does anyone know how to remove the plastic cover for this needle valve. The cover has a notch on it that limits it's movement.
Anyone who can help me with this is worth a gazillion bucks.
Thanks.... Greg

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.