The metric and English units of measurement have quite a bit of difference, but you may need to convert both measurements in order to make proper calculations. Briggs & Stratton engines come with both cubic centimeter (cc) and horsepower ratings. The description plate attached to the top of each Briggs & Stratton engine lists the model number and engine power. A Briggs & Stratton engine with a "CC" rating rather than a "HP" rating will vary a bit above or below the converted HP rating depending on how well tuned the engine is at the time of testing.
Turn the Briggs & Stratton engine upright so the flywheel shroud is facing you.
Locate the information plate attached to the top of flywheel shroud.
Find the horsepower or CC rating listed on the information plate.
Calculate the horsepower or CC by multiplying or dividing by 15. The general rule is for every 15 CC there is 1 HP.
For example, for a 150 CC engine you would take 150 divided by 15, which equals 10 HP.