I have 3 trainer engines 2 evo nt 46 and 1 nx evo 52 all good motors os engine is also good only problem i ever had was with the 52 needed to be broke in better
one thing that happen to me one time was flying the twist carb came out while inverted 50 feet up [X(] (my error i should go over my planes) fliped over landed
bolted back together and flew ....very low mantance if any mantance .

hope this helps .. also like how the glow plug angles back ( safety) i wish os engines did this also