When you trouble shoot a lawn mower there are only 2 things to consider 1) gas or 2) electricity (spark). So you would concentrate all of your troubleshooting efforts to determine which one isn't working quite well. Always consider the obvious 1st to make absolutely sure that the problem is not operators error. Go on with the steps below until you succeed.
Trouble shooting strategy (initial)
1st is it choked when you try to start it? (observe the actions of the levers associated with the carburetor as you move the choke lever on and off when the lever is choked there is a extreme movement to the links closing the butterfly for the least amount of air suction)
Does it have gas in the tank?
Check oil level - add oil or replace entirely (this has nothing to do with starting but make sure to check this anyways)
Is the spark plug wire plugged in correctly? which means you have to unplug it then replug it snug
If it has a primer is it primed? you know the little bubble primer bulb you have to squeeze it several times
Pull starter cord see if it starts.
Trouble shooting strategy step 2
shoot some gas or starter fluid into the carburetor and pull starter cord (if it refuses to start it might be an electrical issue) move on to step 2a. This will require that you pull the air filter cover and air filter off for access to the throat of the carburetor and spray starter fluid or gas directly into the carburetor.
Trouble shooting strategy step 2a
pull the spark plug and replace it with brand new, shoot some gas in the carburetor and pull starter cord.
Trouble shooting strategy step 3
pull the spark plug & plug it back into the spark plug wire
take the loose spark plug and ground (touch) the threads onto the body and have someone pull starter cord - observe whether you are getting sparks jumping on your spark plug. Put on rubber gloves as you are doing this you'll have to hold the spark plug grounded to the body of the motor with your hands.
If you are getting sparks - reinstall spark plug the problem will be in the gas i.e.. Either replace or clean (bad gas, carburetor, hose from gas tank to carb, in-line carburetor filters, in-line carburetor shut off valve) these items. But do the carburetor last. Do not pull or clean the carburetor until you've checked and cleaned or replaced everything else 1st. (bad gas, hose from gas tank to carb, in-line carburetor filters, in-line carburetor shut off valve)
If you are not getting sparks - you may have to change your "ignition coil" or you need a new spark plug. Caution: sometimes the spark is so little that you have a hard time seeing it with the naked eye. Buy an in-line spark plug detector on ebay or Harbor Freight Tools for under $5. And retest for spark.
If after performing these tests and it appears there is no spark there are many youtube videos that show you how to replace an ignition coil. My favorite is donyboy73. He's a pro and is very easy to understand.
What you really need to understand is that small engines are very simple in design and are really very easy to get to start. And I'm talking any small engine. Propulsion on the other hand is a very different issue.
My lawn mower was hard to start (like ten pulls) and wasn't running strong so I decided to clean the carburetor. I cleaned the jets and now it won't even run. After I cleaned the carburetor, I tried pulling the starter cord and it snapped after two pulls so I hard to go back to the store and get another one. This one seems to be a little shorter on the pull, but it won't start at all now.
Do you think something is clogging the lines? I plan on taking the carb off tomorrow again to clean it. What's the best way to trouble shoot it?
