New engines have been inspected to be sure that all parts are present. Dirty engines have been cleaned. All used engines have been test run and adjusted to achieve appropriate high end and idle speeds and smooth transition. All engines have been given a rating according to the following chart.

Rating Description
10 New. The engine has never been run and is expected to be perfect.
9 Bench run only. There may be minor surface scratching, but is otherwise flawless.
8 Flown only a few times. There may be minimal surface wear, but runs without fault.
7 Excellent. Average use. Will have some oil stains and minor surface wear. Operates at peak performance.
6 Great. Moderately used and still running at peak performance.
5 Good. Still operating at peak performance.
4 Fair. Still running well. May have some surface scars (broken fin, enlarged hole, or discoloration). Compression is still excellent.
3 Poor. Still runs, but has poor compression and/or poor idle.
2 Parts engine II. All parts are present, but may not run.
1 Parts engine I. Missing some parts.