Running fuel out of engine

[JRM80000]

I have a 1989 30elf which has been a pretty good engine, but I had something odd happen recently. At the end of the season, I disconnected the fuel line and ran the engine until it stopped to get the gas out of the carburetors for the winter. To be sure, when I got home, I loosened the carburetor drain plugs to remove any remaining gas. The top carburetor had very little gas in it, but the bottom two had quite a bit of gas. Maybe a half cup or so. About a year ago, I went through the carburetors, cleaned and set the float level for all three. I did the link & sync, but have never been entirely satisfied with the low speed operation. It slobbers until I get up some rpm at which time it runs quite well. I'm sure I need to do the cleaning again based on what I have read in this forum, but my question is: What is the discrepancy in the fuel quantity from the top carburetor and the bottom two telling me? I'm confident that the float levels were set correctly and I recall no indication of faulty floats. Any thoughts would be appreciated.

[rodbolt17]

attempting to run the gas out is a bad idea at best.
that's what the drains are for.

[99yam40]

You have one fuel pump that feeds 3 carbs , the top one will run out of fuel before the rest due to gravity.
the middle one will run out next and then the bottom one.

If you are running the motor as this happens the top cylinder is not getting any fuel or oil and is not helping the motor run, then the middle cylinder does the same,
so do not do this any more, drain the bowls as Rodbolt said if you want them empty, it is a lot better on the motor.
The older single carb motors did not have this kind of problem, but they also did not get all of the fuel out of carb bowl before motor died either

[JRM80000]

Thank you. I'm glad i asked. I won't be doing this anymore.