If you mean the engine will rev up and down as it is running, it has been my experience that a dirty air filter is a cause of the fluctuation.
Buy a lawn mower engine repair manual at Border's or Barnes & Noble.
A 5hp craftsman engine has a compresson of 135psi
There should be a sticker/stamp an the engine somewhere. It will give you a few specifications about the mower.
Symptoms of a bad ignition coil on a lawn mower include difficulty starting the engine, engine misfiring or stalling, and poor performance or loss of power while mowing.
very gently, or the mower will get squashed
A 190cc engine in a lawn mower typically produces around 5 to 6 horsepower. The exact horsepower can vary based on the engine's design and efficiency. Generally, smaller engines in the 190cc range are used for residential lawn mowers, providing adequate power for typical mowing tasks.
depends on the engine but it will be on the engine block.
The sound of a jet engine vibrates more than the sound of a lawn mower.
from a distance away why does a jet sound loader than a lawn mower
The pull cord of a lawn mower is used to manually crank the engine to get it started. As the engine is quickly turned, a spark is created which begins combustion.
A lawn mower works by converting chemical energy (energy stored in the gas) to mechanical energy.
Check the underneath of lawn mower for grass built up.