With some recent discussion about floats and needles I thought this might help, rather then digging into all the past topics.
Some OEM Nitrophyl floats will break down with age and start absorbing fuel. The problem comes on slowly. In simple terms - The more laden with fuel the float becomes the lesser the equivalent proportional force applied to the needle to keep it closed against the static weight of the fuel in the tank and line. Running rich and flooding soon follow. This will result in having to frequently "Lower" the fuel level to compensate for the ever increasing Rich syndrome from a sinking float. The float buoyancy concern is easy to verify. Weigh each float on a Pocket Digital Scale. They “normally” will range from 8.4 grams to 11.0g. Anything over 11.0g would give me reason to suspect that particular float is close to the end of it's service life. This should be a reasonably good bench mark to use as a comparison to what your floats currently weigh. You can also pivot the float on a small drill-bit and see where it sits in a small container of fuel. The top I/2 should be above the fuel, as a rule of thumb. If the float sinks when a dime is placed on top of it................"Your OEM floats have served their intended duty and should be discharged from further active service with full honors and privileges”! They make great Key-Fobs!!!!!
The photo is of a OEM float that's been in a drawer for several years so it's dry. And it's in water. Shouldn't be a huge disparity in it's buoyant height if you choose to use gas. Just be careful !