injected engine roughness when cold

[DEWATSON]

I have an IO 360 Titan engine from America Aircraft Engines. I cranked it for the first time Saturday and found that it would run briefly then die unless I turned the boost pump back on. If I left the boost pump on, it would also die. I had to run the pump until the engine stumbled and then turn the pump off until it stumbled. After a while (probably 5 minutes) the engine finally ran smoothly without turning the boost pump on and off to keep it running.

I'm sure it has something to do with mixture while the engine is warming up. Has anyone else experienced this? Do you control the mixture while the boost pump is on with the mixture control until the engine warms up? Is this common?

Nevertheless, after three years of building, it sure was nice to hear it run.

David Watson
49FD
RV8

[asav8tor]

Do you have a fuel pressure gauge reading fuel pressure after the engine driven pump? If yes you need to run in again and watch the gauge, boost pump on/off for more info to diagnose.

[DEWATSON]

No functioning fuel pressure gauge yet. It is included in the FlightDek 180 but not hooked up yet. I'll get it going and check the pressure. The odd thing is that after the engine warmed up, it ran fine......idled great and ran smoothly at all settings. It only gave trouble while warming up. Anyway, thanks for the tip.

David

[David-aviator]

Originally Posted by DEWATSON

No functioning fuel pressure gauge yet. It is included in the FlightDek 180 but not hooked up yet. I'll get it going and check the pressure. The odd thing is that after the engine warmed up, it ran fine......idled great and ran smoothly at all settings. It only gave trouble while warming up. Anyway, thanks for the tip.

David

It's just a guess, but the rough start may have been caused by air in the fuel line. Once it pushed through, things smoothed out. The system found its brain and worked fine.

Congrats on the first start....and may there be many more.