Originally Posted by Ron Stewart
The 150 is 26Gal total (13per side) but only 22.5 is usable. The POH is the go to source.
If you fill your tanks to the bottom of the filler neck and measure with the tube you bought from Sportys and it reads just over 11 gal in each tank then that is usable. If it reads 13 each side then it is total and you need to subtract 1.75 each side to get useful amount.

I don't know how the Sporty's fuel stick is marked, but can we go by this: if the 1-gal mark is very near the bottom end of the stick then it indicates actual fuel level, if it's away from the bottom of the stick (i.e. has a blank area) then it indicates usable fuel level?

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