I have training a buddy of mine on his H9 Alpha 60 with Evo .61 NT engine. The problem is that I cannot a good transition following an extended idle sych as final approach. With glow igniter on it transitions fine. We have gotten a very nice low idle and smooth running at all rpm's, but in transition after long idle without the glow igniter it dies no matter were I set the needles. We have tried 3 OS A3 plugs and the included plug to no avail. Do we need a hotter plug? After 22 years of glow engines this a first for me.

We have also started using a 2 blade prop which did not effect this. All fuel lines have been replaced over concern of air leaks, the bard has been cleaned thoroughly and still it's no better.

This is making him very nervous on landings since powering out to try again usually results in a dead stick. Frequently flying 15+ mph winds is hard to learn to land in.

TIA

I am not familiar with Evolution engines but from what you have described it sounds like you may be just a tad rich on the low speed needle. Try a tiny bit leaner setting and adjust your idle speed up a little. Too rich a setting on the low speed neddle allows excess fuel to accumulate in the engine and can cause a "load up" condition to occur in the engine. Hope this works for you.

Steve

I agree with Mustangman.
When you get the idle about right, throttle respons is good when the engine warms up, and worse with cool engine.
tweak the needle little by little. !/4 turn may be waaaay too much.
Finally, get some plugs of the same brand, in different heat ranges, and check out which performs best.
then maybe change brand, and do it all over again. OS#8 and OS-F are good plugs to start with. Novarossie #6 and #5 are quite good as well, Enya #3 and #4. Just a few of my suggestions.
This is tedious work, I know, but perseverance never failed anyone.

Yeah we have leaned richened both needles vastly in either dircton, but at very small increments at a time. I have an OS#8 plug we can try. That's what I run in my OS 46 AX and my TT50 heli engine. I removed the dang stops on Evo needles since they were far too limiting. The high end needle stop kept the high end running about 1k rpm low. We'll swap the plug and then start the needle dance again.

I am surprised since I have never worked an engine so much with such poor results.

The next step after plugs and re-tuning, although likely not needed, may be to rnu an onboard glow igniter.

The stock fuel lines had a bunch of pin holes in 'em. Swapping those helped a good bit of course.

Thanks guys.