hear the cylinoid but it won't engage the starter

Tap firmly on the body of the starter with a small hammer while an assistant attempts to crank the engine. If the starter engages, then you have a faulty starter. If the starter doesn't engage, try turning the crank with a pull bar and socket, if the engine will turn, check the flywheel for missing or damages teeth. If there is no damage to the flywheel, replace your starter. If the flywheel is damaged, replace your starter and flywheel. If you cannot turn the engine, replace or rebuild the engine.