Greetings,

During the first year of flying my IO-320 I had exactly the same problem.  My setup included a Dukes electric boost pump located on the lower-right side of the firewall and the stock RSA fuel injection system.  It would get hot, fuel vaporized and then just spin in air (which is very hard on a Dukes pump).  Hot starts were a real bugger!

When Orin Riddell came out to do my first flight he took one look at the setup and told me I should relocate the Dukes pump to the floor under the passenger’s seat because I’d have hot start problems.  I dragged my feet but after one summer I made the change.

Now, the pump lays on its side under the passenger’s seat which is at about the same level as the bottom of the fuel tanks.  This way, the pump always is bathed in cool fuel from the tank and never gets even a bubble of air. With this cool fuel and continuous prime, the pump *pushes* the fuel through the rest of the system rather than trying to suck fuel through the vapor bubbles.

My hot start technique now is as follows:

1.       Leave mixture at lean cutoff

2.       Throttle about ¼ of the way open

3.       Crank engine

4.       Once the prop has made about 3 or 4 revolutions smoothly and quickly push in the mixture (engine will fire and the begin to cough and stumble)

5.       Very quickly turn on the electric boost and engine springs to life.  Probably will need boost pump on for about a minute to purge all the vapor from the system.

6.       Boost off once the engine is running smoothly

7.       Make sure to do a good run-up before takeoff to ensure all vapor is purged from the lines.

I hope this works for those of you with the hot start issues on the IO-320 and IO-360 engines.

Cheers!

Dan Olsen

N320DK – 500hrs

Fort Collins, CO