Based on your measurements and calculations (exercise 13), what is the compression ratio, CR, of the lawnmower engine?

Refer to a 3.5 horsepower lawn mower engine at a nominal speed of 2.50 × 10³ RPM. A typical lawn mower engine, and the inside of its cylinder head, is shown below. Note: the depression in the cylinder head is the clearance for the engine’s valves. If such an engine is available to you in class, you can disassemble it and measure the bore, stroke, and clearance volume, CV, of the engine.

Valve clearances Piston Valves Fully assembled engine Partially disassembled engine