I have a alpa 40 trainer with the evolution power trainer system in it. I am still fairly new to the hobby and i'm not very good at tuning the engine yet. I can get the engine tuned good before flight to where it runs good at idle and at full throttle, but sometimes when i push the throttle to full it sputters and dies and three times when i was flying yesterday the engine was running great and then it would just die on me. I had to make three dead stick landings but when i got it on the ground it would start right back up and run great. Is anyone else having a problem like this? Any help would be greatly appreciated. It really sucks flying when you can't trust your engine. Thanks

You are not kidding.

Sounds like it's rich, probably mostly on the low end.

Set it on the ground, wide open throttle, lean out high speed needle to max RPM, then richen a few clicks to the slightest noticeable change in pitch. Drop to idle and let it sit for 20 seconds. Listen carefully to the rpm while sitting at idle - if the RPM drops you know it's a little rich. After the 20 seconds, advance steadily to wide open. If it spudders, low end is rich. Adjust in very small increments and re-do the process again.Your RPM should not drop during idle and should not drop when you remove the glow ignitor.

Mods, can we get a sticky on engine tuning? Maybe in the beginner's links above? Just a thought.


Oops, I forgot it was an Evolution. They have those stupid limiters that don't let you properly tune the engine. I would do a search on how to remove them.

+1 for a rich low end. Joe explained the tuning process well. I will only add that if the engine immediately dies upon increasing the throttle then it is likely you turned the low speed needle in too far.

I've had a few years experience helping people with this engine. The thought that the low speed needle is too rich is probably correct. These engines are extremely easy to set up and run correctly. Next time you go out to fly take your engine manual with you and follow the step by step instructions given for adjusting the engine. You should get it adjusted just fine that way.

I would also check the fuel tubing everywhere in the system for a small nick letting air in.