Translations:KAVAN AP09 - Instruction Manual/119/en

Breaking-in

Note: Since the piston of this engine is not equipped with a ring but is machined to move tightly in the cylinder liner (type ABC - Aluminium piston - Brass sleeve - Chrome plated/Aluminium piston in chrome-plated brass sleeve), you will feel considerable resistance when turning the engine. This is normal. Once the engine has warmed up to operating temperature and is properly broken-in, this resistance will decrease and the correct backlash for operation will be achieved. Under no circumstances should you attempt to disassemble the engine or modify the friction surfaces of the piston in any way. This will only void the warranty. Simply follow the break-in procedure described below.

1. The break-in process allows the engine parts to perfectly fit to each other and properly protect the parts against unnecessary wear. The fuel used for break-in must not contain more than 15 % nitromethane and no less than 20 % castor oil. Do not use fuels containing synthetic oil during breaking-in. For break-in, we recommend installing the engine in the model in which it will be operated in the future. This will allow you to test and adjust not only the engine, but also the entire fuel system and RC throttle control. If the model has an engine cover, it should be removed for breaking-in.
2. Refer to the Recommended propeller section and select the correct propeller (7x4“ is recommended).
3. Start the engine as described in the Starting procedure section.
4. Once the engine starts and is running, open the throttle fully and open the needle valve to a very rich mixture (unscrewing the needle enriches the mixture). Let the engine run for two to three minutes. Then turn it off.
5. Once the engine cools down, restart the engine. Set the mixture to a slightly leaner setting. Let the engine run for a few minutes and then let it cool for 10 minutes.
6. Repeat this process while slowly leaning the mixture for each run.
7. In total, you should let the engine run for about 30–40 minutes. The engine is fully broken in when it maintains maximum RPM at full throttle for 5 minutes without fluctuations or overheating. After completing this break-in procedure, the engine is ready for flight.
8. Fly the model with the engine set to as rich mixture as possible and with an adequate power.
9. After each flight, lean the mixture slightly. Continue to do this, until the engine is holding a normal needle valve setting after 10 flights. Remember, do not over-lean the mixture.