lml@lancaironline.net Mailing List Archive

My experience matches Dan's. My IO-540 powered ES was built with the electric pump flat on the floor under the seat and has never had a problem with prime. The RSA fuel system, in contrast to the Continental, has no fuel return, so whatever vapor is in the system has to be purged through the engine. That makes for some rough running and potential stalling after a hot start. Yes, there are purge systems available that will certainly help, but I elected to keep mine simple. I added a tight box around my gascolator with an air scoop for cooling and air from there goes to a shroud around the engine pump. Works well while running but a hot soak will still cook the fuel in the system. Only problem is that the rough running and surging right after start makes the passengers nervous.

Gary Casey

ES #157, Colorado

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