How long after fuel stops flowing before the engine quits?

I would only depart on BOTH or ON if that is all you have.

I believe the cycling of the fuel selector is not a flow test, but more of a "Is the handle going to turn if I ever need to move it" type of test.

Some owners might place it in BOTH and never move it again for years otherwise.

It it is not regularly cycled, it could be frozen in position and you would never know.

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An interesting feature of the Fuel Injected engines is that if the Fuel selector if turned to OFF, it produces the same result as shutting OFF the fuel pumps;  The engine stops within ONE second!

I don't have a BOTH I have an OFF or LEFT or RIGHT.

Glenn Martin wrote:

Yeah....do not do that...

  I know at ide often a student forgets to turn on the taps and they seem to get about a minute at 2-3000 so say quarter that at power setting, maybe only 15 seconds ?

This will not hurt the carbs by drying them out or the engine. Athough the impact with the ground will not be good for the engine.

I would not do it in the air! ?

Pilot Joe wrote:

I don't have a BOTH I have an OFF or LEFT or RIGHT.

In that case, Cycling the selector may just be an exercize in limbering up the seals.

I was going to suggest that you set the selector to OFF and when the engine starts to stumble select either side to confirm flow.

This is would be redundant if on the previous flight you ran off of each side for more than 5 minutes confirming flow.

Do you you routinely select OFF between flights?

If so, will the engine start and run for any appreciable lenght of time if the selector is kept in the OFF position after hangared for a few days?

If you know that the first flight of the day will not make it to the hold line without real flow, that should instil some confidence that the engine is Not going to falter crossing the departure end.

I don't select OFF ever. I shut it down in either LEFT or RIGHT.