I enjoyed building this engine. Yes, occasionally there may be a missing screws but rarely a missing part. Instructions could be a little better. For instance, Installing the Hall Effect Sensor that inserts into the side of the distributor. From what I saw, it looked as if it would insert perpendicular to the engine plane (left to right) but that was not the case. After removing the distributor and disassembly, I discovered that inserts parallel to the engine perfectly. The shrink tube must be delicately removed from the sensor so the entire surface of the sensor is exposed. Additionally, I had to file a small relief into the nylon pieces so the distributor could be reassembled. Make sure it's all the way in. Once you know your getting spark, you may want to secure it with a drop of super glue. Throttle settings can be finicky as is the case with most of these little engines.