A hard starting lawn mower can be a real pain to get started and it can be even harder to start after you shut it down for a minute or so to pick something up from the yard.
Hard starting is generally a carburetor choke problem or a valve issue. But there are other things that can cause it and they will be covered here as well.
Choke springs or incorrect setup of the choke can make your engine very hard to start. It will not be resolved until the choke is repaired properly and tested when the engine is cold and hot.
A valve issue is a little more complicated. A valve could have a lot of carbon buildup on the valve stem causing it to stick open or closed. Or the valves could be out of adjustment. A good lawn mower mechanic can adjust the valves and get your engine starting much better and easier. A pull start lawn mower should start within 2 pulls of the starter cord. A riding lawn mower should start within a few revolutions of the engine. Another thing that can cause hard starting is a valve seat that is coming loose and not sealing well. The seat will have to be replaced to correct this issue.
One more possible scenario is that your air filter could be so clogged that the engine is not getting enough air to start. Check the air filter to see what condition it is in and replace it if it is suspect.
Your engine could also have a leaking head gasket. A compression and leakdown test will need to be performed to see if that is the issue here.
Lastly, you could have water in your fuel or the wrong fuel in the fuel tank. It is not uncommon to see diesel fuel filled gasoline tanks, so if the fuel is in doubt, drain the tank and carburetor and refill with fresh fuel. Check our locations page for a shop nearest you.
I hope these tips will help you get your my lawn mower is hard to start back up and running once again.