I was mowing and my mower just cut off. Looked at air filter it was nasty went to store bought new. Put new on would not start. Now if I put my hand over the intake hole with a glove on mower will start run really bad but will run as soon as I move my hand it cuts off. What is cause mower not to run.
Sounds very much like you have a clogged carburettor but it hard to work out from the words you typed
Remember we can not see the mower all we have is your words .
Nasty = saturated with fuel ?
Saturated with oil ?
Choked with dirt ?
rusted away ?
Fallen apart & 1/2 of it missing ?
Runs really bad
= coughs & farts ?
= misses ?
= revs up & down ?
= backfires through the carb ?
= backfires through the exhaust ?
= blows black smoke
= blows white smoke
= spits fuel out the carb
Well that one is easy you are not getting fuel. LOL Could be a fuel delivery problem to the carb. Fuel pump, fuel solenoid, water in fuel, fuel filter, fuel tank not venting. Remember KISS don't throw parts at it trying to find the one that fixes it. Some people that don't know what they are doing call this the process of elimination. Yea right. Mostly costly fix. Check to see if you are getting fuel to carb. and go from there. Make sure the fuel solenoid is working listen for it to click when you turn the key on. Look for trash in the tank.
Lack of maintenance momma, lack of maintenance. Steve Lav.
Either a sludgeberg of oil and grass fell into the carb when you removed the sludgeberg air filter or it hyperventilated when all that air rushed into the cylinders.
Your carb is dirty. That air filter was artificially choking the engine for you. Now you have proper air flow (clean air filter) and the carb is running too lean.
Dump the fuel tank and super clean it out too. Probably a bunch of grass and grit in the bottom.
Clean out the entire fuel system. New fuel lines, filter and shut off valve.
