Marcel, I looked in the manual and I can't find a "factory starting point" for the needles. Checking my engine, a used one that I've never ran, and I found the high speed needle in a bag. I"m going to guess that the idle mix is about right. The head of the screw is about 3mm in from the outer part of the barrel that the throttle arm mounts on. So, here is what I would do.

Start with the idle mix about 2.5 mm in from flush with the outside of the barrel. Start with the high speed open three turns. That should get the engine running. Isuggest starting here rather than where the engine is now at as needles are a balancing act and is hard to know really where you are starting from.

You mentioned that it was inverted, I suggest you mount it on a test stand until you get it running very well then mount it in the plane and just fine tune it there.

Fire up the engine and let it warm up a bit and then go full throttle. Lean out the high speed for max RPMthen go rich 300 to 400. You need a tack to find this point. Now, set the throttle to the slowest speed that will keep the engine running. Leave the throttle there and very slowly lean the idle mix to get maximum RPMat that throttle setting. Note, if the needle is stiff as the one in my TT 91, you may need to hold the throttle arm with your hand while turning the idle mix. When you have found the best high speed setting, then go back to the WOT again and re adjust the top end. Go back again to the slowest idle you can and keep it running and again without changing the throttle adjust for max RPM. At this point, you should be able to idle at around 2200RPM. If it is higher, go back to the high speed and adjust it again and then back and fine tune the idle some more. It may take as many as four trips to get a balanced adjustment.

Now you have to fine tune the idle mix for transition. Run the engine up full throttle for a few seconds then go to you idle. Let it idle for 20 seconds or more then as quick as you can go to full throttle. If the engine slowly gains RPM, or stumbles a bit before gaining rpm, the idle is too rich and needs to be leaned a little more. Go 1/16 turn at a time until the engine jumps to speed when you hit the throttle. If the engine just dies when you jam the throttle, it is to lean. Adjust out 1/16 turn at a time until it jumps. It should respond very quickly to throttle when adjusted right, and with the right prop.

Once you invert the engine, you will need to fine tune both needles. A glow driver may be needed also depending on the engine. The common problem is idle issues as it is easy to flood the glow plug when the engine is inverted. If the carb is adjusted to peak on both ends, it should be OKwithout an on board glow driver.

If you don't have the manual, send me a PMand I'll send you a copy.

Last, the puff of smoke when you hit the throttle is good. You are not far off from where you are at now.You may get away with fine tuning from where you are at now, but Ipersonally would start from scratch and go from there.

Don

Don