Jorge - Just last week, I ran-in a new TH75. Just some observations for ya .....

I used an APC11x6, 15% fuel (18% oil), tower plug that came with the motor, and a pitts style exhaust. Per the manual, I had the HS needle at 4.5 turns out. Put alittle after-run oil around/on top of the piston, and it fired right up. Ran it WOT for the first and second tank. I did lean the HS needle a half-turn or so during the first tank .... it was 4-strokin abit. RPM was upper-12K's for those first 2 tanks.

The 3rd tank, I put an APC 12x6 on it, and again ran it at WOT taking note of head temp as I leaned the HS abit more. RPM's were low-mid 12K's.

I did run one more half tank or so, working on a decent transition so it would be flyable. I should mention that I did let the engine cool completely between each tank.

I've now got about 1.5 gallons of fuel through it, and its getting better and stronger with every flight. After each flight up to this point, I've made small changes to both the HS and LS needles, and also paying attention to head temp. I've also changed to an OS#8 plug. At this stage, I've found that a Zinger 12x8 prop is best .... but that is sure to change as I make needle adjustments. I should mention that I'm not looking for speed ..... I want power and pull for the Big Stick 60 its mounted on. I tried a couple of props in the 13" diameter range, but didn't like them. I'm still alittle more than 3 turns out on the HS needle so its still on the rich side ..... but its smooth, has an improving idle and a nice stream of smoke.

Couple of things to watch out for .... both carb related. At some point during the second tank of breakin, the carb barrel stop screw backed out. Since the engine cylinder is mounted horizontal ... this allowed the carb barrel to pretty much drop out. Didn't notice it until after the engine burned the whole tank of fuel .... how long it was like that, I dont know. That screw, as well as the carb hold-down nut has a generous amount of thread lock now. The carb body itself is the second part to watch out for. For most of a gallon of fuel, I was having trouble shutting off the engine with the Tx throttle-cut. I knew there was an air leak somewhere, and had covered all the bases of culprits .... including reading ALOT of posts about defective carbs on the TH75. I'd already had the carb off a couple of times and was sure I had pushed it down into its mount sufficiently....and then tightened the nut. On saturday, I decided to try it one more time ..... with the engine warm. Loosened the nut, and pushed the carb down for all I was worth .... ..... tightened the nut, and Ba-Da-Bing!! No more air leak! And the engine shuts down everytime now.

I flew the plane about 10 times on sunday ... and the TH75 is fantastic!, and getting better all the time!

Your mileage may vary, but I hope my very recent experience is of some help to ya!

FlySafe! Larry (Larrys4227)