La Engines
What killed the LA series engine was the .46. although it can be reliable engine, it simply lacked the power that most people "EXPECTED" from a .46. part of this was because some were trying to run it at high RPM, when it is not ported for it, Some did not give it enough break-in time, I found using larger props like 11-6 and 12-6 worked much better than 10X6 and 7s . MANY of the LA .46 engines had problems with the remote needle leaking as well as back plates leaking (I had this problem myself on several .46s) . Because of the expectations of the .46 it was purchased more so over the .40 , so you can expect a higher number of problems. IMO "The step back" was in the Plastic Back Plate and remote needle carb , I also read somewhere here at RCU but have not verified that The LA liners are thinner, don't know if this is good or bad. With the FPs you would sometimes break the needle and spray bar in small crash, it could be replaced easiely in most cases, I even soldered many back together, whe the plastic remote breaks it sometimes breaks the backplate as well, the engine must be removed to repair, the plastic backplates bolt lugs will eventually come loose , you can only tighten them so much, even with lock-tight the plastic will eventually give and leak. O.S did not make a .46 fp so you can't compare them, but the last Generation of FP 40s (and tower .40s) turned the 10X6 props just about as well as the .46 LA did (but not bigger props). I have ran the .25 L.A. and the .25FP and it runs about the same but the L.A. is still a cheaper built engine, I would not say it is CRAP, but I do not like the plastic parts. IMO the LAs were a Slight Step Back , The FP series worked , there was nothing wrong with it, there was no reason to change it, and IMO the LAs are not as good an engine as some of its competitor engines like the TT GP 25 and 42. In both performance and quality. I really don't give a rats tail about the looks of an engine, but if it works, don't fix it.