Russell,

Some questions first.  Are you saying that the pump did not turn (no noise at all) or that it would not develop pressure but did make noise?  Be sure the cockpit is quiet and your headset is off your head.  You should be able to hear the pump.  When it is pushing fuel it sounds a little labored.  That is good.  When it is dry, it spins faster.  This is bad.

If no noise at all,  does anyone know if there is a thermal overload circuit in the Dukes pump?  Does it reset itself when cooler?  If true, then you are probably OK, Russell.

If no pressure, this just sounds like vapor lock.  The high heat evaporates the fuel at the pump and it can not push the air bubble.  Be careful to run it only a few seconds at a time in this condition.  The pump can not be run dry for long, it overheats and will destroy itself quickly.

In general with the vapor lock, you just have to use a good hot start procedure.  This varies from Lyc to Continental, you did not say what you have.  This works for me in an LNC2 with Lyc IO-360.  When heat soaked, more than 15 minutes:

1.  Mixture off.

2.  Throttle about 1/4".

3.  Engage starter.

4.  At first fire, full mixture and Dukes fuel pump as required.  The engine will be very rough until all the air is purged.  Fuel pump off as soon as the mechanical pump can keep the pressure in the teens or better.  If the engine does not start on that first try, the likelihood of another try right then is very low.  You got a burp of running from vaporized fuel down stream from the servo, and once it is gone it will be difficult to pump more until the engine cools off.


If you can do a very fast re-fuel or pax swap (shut down for just a couple minutes), then:

1.  Mixture full.

2.  Throttle about 1/4".

3.  Dukes pump for about 1/4 to 1/3 of the time you would use for a cold start.

4.  Engage starter.

5.  At first fire, full mixture and probably much less with the Dukes pump.

Good Luck,

Tom




Russel wrote:

"Yesterday after flying into a field the Dukes of electric fuel pump would not run at all. I was forced to leave the aircraft at the field because I couldn't get the engine started.

The field elevation was 1300 feet and it was close to 90°. The density altitude was about 3000 feet for the day."