ORIGINAL: Fastsky
Agree with Ed that some engines don't make good first engines. The ASP Super 52 is a superb running high out put engine but it takes several tanks of patient break in time to get it there vs. 3 tanks and ready to go for the OS and TT engines.
Gosh, mine was perfect right from the first tank-full. Didn't seem to need any running in and apart from one deadstick, has been 100% reliable.
Perhaps it's because I just tuned the needles and flew it like I stole it rather than going gentle on it for the first few tanks. Now has great compression, starts easy, pulls well and never stops unexpectedly.
I still prefer the TT46Pro though. The Magnum/ASP mufflers are rubbish and they're still using two bolts to hold the carby on (lost one on my second flight, the only time it's ever deadsticked) rather than the more effective pinch-bolt setup.
The bearings in both my 52s were also a little noisy right from the start whereas all my TTs have been *smooth* as silk and only one has needed replacements but that was after 220 hours of running.