My 18 hp vanguard surges the rpms are up and down causing it to stall out at idle. Even when you give it gas you can still feel it surging. Cleaned everything out but it still surges

Hi,
Well, you may have cleaned everything but there is still some dirt in one or both of the low speed circuits. They are the smallest so are the most easily clogged. Your engine is a V-twin made in Japan and probably has a Nikki carb that looks like a 2-barrel though it actually has a balance system where the whole carb supplies each cylinder as needed. The pilot jets are generally removable though they could be well buried. I have had luck with a hypodermic flushing backwards through the jets to clean them in the past.
Peace,
Clarke