I've just purchased a thunder tiger pro .61 to power my 60 size Extra. I've put 4-5 12oz tanks through it and it still runs HORRIBLE!! I can't seem to tune this thing at all. First off, it starts fine, runs and transitions well when it's cold. It is mounted under a cowl, but has ran this way with and without the cowl. The motor is mounted on it's side with a Slimline pitts muffler, which I've tried restricting and that didn't help. I'm running a 11X6 prop for break-in and a fox glow plug with idler bar. I'm also running 5% fuel which I've never had a problem with any other engine. Most of my experience has been with OS and have had nothing but good luck. The only reason I went with the Thunder Tiger was for information purposes. I help at a hobby shop and we just started carrying TT and I wanted to know first hand what they were all about. So far...not impressed!

Ok...the symptoms. High RPM's are great. If I run it at full throttle for anything longer than 30 seconds or so then drop it down to idle, it will die. The transition from idle to half or full throttle seems like it's rich. But, if I lean the bottom, the motor will not start. I've played with both needles but without success. I've checked for leaks, and such. It's got brand new fuel lines, new sullivan tank, etc. I'm wondering if 5% is not enough or if I need a different glow plug? The other issue is on the ground, the high needle setting seems great. When held up the engine does not lean out. But, once in the air the motor seem rich. Not getting full RPM at all. This was also on the 3rd tank or so and that might just be break-in. My major concerns are with the transition issue and the fact the motor won't idle once dropped from full or 3/4 throttle. It'll slowly drop RPM until it dies. Any help would be greatly appreciated!! Thanks a bunch!!

Dave