Aero nut. This input you gave is what can help. The carb you mentioned the WT433 and the engines that may work best. I agree for sure on that right tunning is really important. I try to run this engine at least 3 times a day. In A.M. (cool temps) around 1 PM and about 6 pm. Now this morning it was cool and damp. It ran good to my surprise. A sign of this is when I start it... it runs in the right direction. when it starts and wants to run backwords, even when I get it running in the right direction...it runs un stable! The carb I have is a WT25 with a 333 below that. The Wt number is not that clear...may be another number. Also I will get another OS "F" glowplug. I was hoping to see more input from others. I placed a post in several forums, asking RC folks to post here in this forum what data they may have. It is still early ...maybe with a few more days more people will reply. I have not ran my engine up in the air yet on a airplane...but It looks like the exhaust is not messy like a regular glow engine! Best Regards Capt,n