Hi, I have a YS 110 in my synergy 90 3d. Its spinning a 15x8 prop on yamada mix 20% fuel. I have had a lot of trouble getting it to Idle at 2000 rpm, the closest I can get is about 2100 rpm, but she seems to be hunting around this point until after about 20 secs she quits. She also seems to be getting extremely hot during a ground run and if it cuts after a short ground run, on restart the engine goes wild and completely erratic with very little trottle control revving up and down at will (after letting it cool down this is cured) During flight the engine seems to run ok, although on a number of occasions it has nearly cut during pickup. My high end needle valve is set at 1.5 turns out, and my low end needle is also 1.5 turns out. For max rpm im getting just over 9000. Im thinking about changing to a fuel containing synthetic oil???
Any suggestions???
Look forward to your responce.

Lee

Oh, forgot to mention that I am de-pressurising the tank after every run. Help!!!

I never try to get one to idle at 2000. 2200 to 2400 is more reasonable and easy to get.
The overheating issue is something else. It could be the fuel, or it could be that you just have the top end set too lean. Have you adjusted the regulator? If not, it may be set too lean as well. Try opening it 1/2 turn and let me know what happens.

Dave

ok dave, many thanks for you quick responce. I'll keep you updated

I'll be waiting.

Talking with a YS engine guru over here, he seems to think the problem could be due to an air leak around the back box, ie a damaged airbox seal, do you think this is possible?

Possible. The airbox is prone to leakage and will cause big problems if it does.

Dave,

Ran the engine up today, tried a different fuel (prosynth 2000 20%), and she idle's a treat, and didn't get hot at all. The midway transition seemed a bit lean, so I took you advice and opened the regulator adjustment a small amount. Now seems to be running ok (although ambient temperature was very low today). Will try again on a nice hot day. Will keep you posted!!!
Many thanks for your help.

Lee

Interesting that the fuel would do it, although I have heard of some problems with the fuel you were previously using. A lot of times what happens is that the fuel mfg's sometimes don't get the fuel mixed properly in the vat prior to bottling. Who knows?

Keep me posted on your progress.