Hi, I`m having trouble with two 1.08 engines. They are 6 years old and I have changed the piston, ring, sleeves, low needles and all O-rings and gasquets. They worked fine for about a year, one in a world models extra 300 and the other in a C.G. Sukhoi. Now, the problem with both is that they do not hold their peak rpms, they are easy to start and maintain idle all day if you want all the way up to about half throttle, but as soon as I take them to full they heat up and die without warning of any kind. Any comments are welcome.

Just for information purpuses, the engines are running on 15%nitro two stroke fuel, when they were running good they gave me about 8000rpms on a master airscrew 15x8K prop. I have used them as I said for 6 years and did not have any problems with them. When the problems started I tried everything and ended up changing the parts mentioned above, and they worked for another year and the problems started again. BTW it is fitted with a slimline pitts muffler the one that has a fitting for smoke.

i don`t want to buy more engines and these 1.08 are incredible powerhouses, easy to use and safe. but.....
Any help please?!?