I'll let some of my more experienced fellow RCU members comment as to your choice of the F-18 for your first fuel model. Break in goes two ways. Take your engine out of the box screw it to the plane and do like some guys "break it in in the air". If you do you will never see the full power potential of your expensive engine. It may even have a short useful life. You may have difficulty getting it to idle and transition well. You may then abandon the fuel powered ranks disappointed. However, if you are patient and resolve yourself to the fact that you may run 1/2 gallon, 1 gallon, 2 gallons of fuel through it before it's really ready to perform - you are in the game. I believe that an ABC engine will require less break-in time due to it's prcision chrome bore. Feel free to correct me guys. Should your engine have a cast iron piston and steel cylinder liner a protracted break-in is advised. Don't look at engine break-in as drudgery. It's a great time to get to know your engine, it's quirks and needle settings for quick start-up at the field. I would run at least 20% lube on a new engine. I run 25% and 5 - 10% nitro. Run a prop that's on the small side in terms of diameter and pitch to keep the loads down on your new engine. Make five to ten short runs at 1/2 throttle with a very rich smokey mixture. Five to ten more with short burts to full throttle and back down. Remember to run small amounts of fuel for 3 - 5 minute runs. Let the engine cool completely between runs. I would, to be safe make 5 - 10 additional runs with the engine frequently at full throttle for more extended periods backing down the throttle occasionally. At this point you should be good to go if your engine will hold a steady full throttle needle setting and not warble or waver in RPM. Remember when starting your engine and setting the high speed needle, reach a maximum RPM listening to the engine pitch and then richen (counter clockwise turn of the needle) 1/4 to 1/2 a turn because your engine will lean out in the air and may cause overheating.

I'm sure you will get additional feedback from the guys - heed it. I'll be following this thread too.

Good luck,
Bill