M20C 48 gallon tanks usable fuel

[Hank]

9 hours ago, Skates97 said:

One thing I always check both before flight and during flight is to run my finger around in the cup for the selector to make sure nothing has fallen in there that could jam it when I go to switch tanks. 

I like to switch tanks just before or just after engine start.

[Greg Ellis]

21 hours ago, Hank said:

If you've ever flown in turbulence, the "crud" you are worried about has been shaken off the bottom of your tanks and burned . . . . Especially if your selected tank was less than half full at the time. It doesn't magically wait until the last inch of fuel remains to leap up and into the fuel port.

It actually does not even take turbulence to stir things up.  I read somewhere and I cannot recall or find the source now (so this is going to sound like anecdote) that even taxiing on the ground will stir up anything that may be in your fuel tanks.  The fuel sloshes around quite a bit even while taxiing.

[Greg Ellis]

23 hours ago, Tcraft938 said:

 

Learned a lot from it.  One I should have right then and there, started putting two gallons at a time in and see how accurate my measure stick is.  I also learned that my fuel gauge reports lower volume than actual (at least the left tank, I need to test right next).  However, don't get cocky and plan on that.  I flew comfortably for more than 30 minutes past the reported ZERO, so that is a nice reserve that hopefully never will use.  Even the Fuel Calculator (JPI) which monitors both tanks, said I had 3 gallons less than I really did.  Again, good to know and I would rather have it read a little lower than give false sense of security.  

 

I am one that has ran a tank dry on long cross countries many times.  When I had the old fuel gauges in the cluster in my 63 C model, I would experience the same thing you did.  It would keep running long past when the gauge read empty.  So those old gauges weren't even close to being accurate.  But don't rely on the fact that you may have reserve past when these old gauges read empty (if that is what you are referencing).  The next time you fly they may read zero when you are actually empty (what they are supposed to do according to the FAA) or they may read that you have some fuel when you are actually empty.  This happened to me on more than one occasion with these old gauges.  From flight to flight they read differently.  So the only thing I relied on was actual loss of fuel pressure and then a good watch to keep track of time and fuel burn.

Now, with my EDM 900 and CEIS fuel senders, they are amazingly accurate.