My lawn mower cranks but wont start I have

I would suggest making sure it has fresh (new) fuel. I would also check and clean the air filter (sometimes little creatures will nest in there). Change the fuel filter, they have a tendency to gum up over the winter. I would also suggest replacing the spark plug.

you may want to check the fuel pick-up and filter inside the fuel tank... sitting for long periods of time with gas in the system can create a 'shellacing' effect, effectively sealing the filter

bad plug (replace plug), bad gas (empty gas, remix to mfg specs, refill tank), improper oil to gas ratio (see bad gas), old gas, choke in off position, corrosion between plug & plug wire (under spark plug boot (pour freshly opened coca-cola on corosion then rinse with distilled water repeat if needed)) clogged air filter (clean filter or replace). if you have visually inspected & or tried all suggusted here & still no joy, take it back to store if it is new, or take to repair shop for maintance.

Spark and gas??? Must have both. Pull spark plug wire and check for spark. If you have spark, check gap on spark plug. Check the bowl on carburetor. loosen bowl screw to see if gas is coming out. If you have gas coming out, carb needs to be taken off and cleaned or rebuilt.

they go bad rarley make sure your blade brake switch is not ingage killing spark

Does it turn over? If it does, what happens? Does it sound normal when its cranking? I need more information to help. Is it a push mower or riding mower? Does it start by key or pull start?

check gas tank with light is there dirt in tank? did you change fuel filter? is there spark at the spark plug? try a 2 second spurt of starting fluid in carburetor and crank does it fire?if it does then you most likely need to clean carburetor with carburetor cleaning spray, flush fuel lines with spray and swap fuel filter.

Possible Causes Corrective actions
Unit will not start Control handle is not engaged Engage control handle
Spark plug wire is disconnected Connect spark plug wire
Fuel tank empty or stale fuel Replace with clean, fresh gas
Blocked fuel line Clean fuel line
Faulty spark plug Replace, clean, or adjust gap
Engine flooded Wait to restart, do not prime
Air filter filled with dirt or debris Replace or clean air filter

Does the motor even turn over. Have you checked the carb. for gunk or gas trash.

if you bent the blade most likely you bent the crankshaft too.
Remove the spark plug and pull the rope and remove excess oil from the spark plug hole
check the spark plug for spark if you have none then a flywheel key is sheered a more in depth fix.
If you get it started you may notice a whole lota vibration due to a bent crank shaft or maybe not?