HI have engines running for many years and still going strong some 400-500 10 minute flights and STILL strong all mine are two cycle glo i run only MORGAN OMEGA PINK FUEL now flying 20 years-ran MORGAN COOL POWER the first two years -shortened my bearing and cyclinder life FAR TO MUCHTHE ENGINE DESTROYER ( CRULE POWER )with omega i do not remember the last time i needed bearings or a liner (18 YEARS ) they need castor oil !-MY OWN OPINION IS THAT THE BREAK IN PROCEEDURE IS WHAT DETERMINES ENGINE LIFE-getting those internal engine parts -POLISHED FROM THE GET GO IS THE KEYthen running the engine correctly regarding the needle valve settingsset the top by ear to max RPM and back off a 1/4 turnset the bottom by running the engine about 1000 rpms above idleturn out the low end until the engine gets a little bit roughturn it in until it gets as smooth as is possible-do that twice- top and bottom now i pinch the fuel line both top and bottom to listen for some RPM increasethat is telling you those settings are a bit on the rich sideAS YOU WANT THEM- IF FOR ANY REASON THE RPMS START TO INCREASE AT THE USUAL NV SETTING ( AND SEEMS ODD ) YOU MOST PROBABLY HAVE AIR GETTING INTO THE ENGINE SOMEHOWFIND IT OR IT WILL OVER HEAT THE ENGINE BY MAKING THE ENGINE RUN LEAN ( EXTRA AIR ENTRY IS THINNING THE FUEL MIXTURE ) HEAT AND SOFT ALUMINUM DO NOT WORK WELL TOGETHER if the engine surges or cuts out during your flight (and you are at full throttle )your top end is to leanrichen 2-3 clicks - just my .02 cents and some basic glo stuff ENJOY REGARDS TONY