Evinrude carburetor

[stratosjoe]

about the only way, carb cleaner sometimes sprayed thru the throat in moderation if its not to bad.

[Embrey]

that still isnt gonna get the jets clean, if thats what it is...

[billm_usa1]

If your loosing it at top end i'd suggest that you've got a fuel hose problem.
The new gas formulations seem to be attacking the older fuel hoses. If yours is the original hose, I'd replace it.