Unless you ran the engine lean it is probably not worn in only 30 flights. Here are a few things to check:

Fresh Fuel- I hope the fuel is not 3 years old too.

Good glow plug- Use the inexpensive OS A3 plug works great.

Check the setting of the low speed needle using the pinch method. Just pinch the fuel line going to the remote needle shut and see what happens. If it takes more than 4 to 5 seconds to start to die it is rich. If it immediately dies it is lean. Remember this engine has an air bleed adjustment for the carb and it works by letting in more air or less to set up the mixture at idle. Open to lean close to richen. Adjusting the low speed will affect the setting of the high speed needle but not the other way around. Also make sure you are adjusting the air bleed and not the idle stop screw which is on alot of these engines. I can not remember if the LA 40 has one. Also, I have always believed that using a 10x5 prop instead of a 10x6 would yield better climbing performance from this engine. A 11x4 would give the most thrust for a Fun Fly plane.