Iv'e been down the engine road for a ton of hours & many different brands over the years. I no longer buy OS engines of any description -- they just aren't worth the price anymore & they seem to have become more troublesome in recent years. I ditched my .46 FXs because of endlessly recurring flame-outs. I never did personally experience a peeled liner, but the engines just didn't work as nicely as others that I own.

My personal preferences at present are:

1. TT.46 & .61 Pro -- great price & excellent value, beautifully made, easily matches the OS engines for power, runs like a jewel right out of the box, lasts forever

2. LEO .46 & .61 Pro-- terrific price, very good value, high quality, very reliable, a bit less power than the TTs, but still very strong, easy break-in, very long lasting, parts interchangeable with MECOA & OS SF series

3. GMS .47 -- terrific price, good value, decent quality, great power (but only with the tuned muffler), prolonged break in, fussy to tune, good engine for risky applications (who cares if it bites it?)

4. MECOA .46 Tomcat -- good value, fair quality, good power, prolonged break in, fussy to tune, very long lasting, good engine for risky applications


The LEO .46 Pro & MECOA .46 Tomcat are both OS SF clones, but the LEO is cheaper, of much better quality & produces about the same power. The LEOs are made in Taiwan by the nephew of the owner of Thunder Tiger. The GMS is a shaky choice because there seems to be a fair number of duds along with a lot of really good ones. My GMS had carb problems, but made a bunch of power for a low price.

My suggestion is: Buy the TT Pro or the LEO. Both work really well & both respond well to tuning. The TT has a very restrictive stock muffler & the application of a Tower Hobbies/Hobbico/GMS tuned muffler really makes it go -- easily outpowering the GMS with the same muffler. The LEO with the noted tuned muffler produces about the same power as the GMS, but is a much nicer piece of work.