Why your mower will not start after sitting
The push mower ran fine in October and will not fire in April. What old gas does to a carburetor, what to try at home, and when to bring it to the bench.
The call we get most in spring goes like this. The mower ran fine at the last cut in October. It went in the garage. Now it is April, the grass is up, and the thing will not start. Nothing happened to it. It just sat.
That is the whole problem. Sitting is the hardest thing you can do to a small engine.
What the gas does while the mower sleeps
Gasoline does not keep. The light parts of it evaporate, the ethanol in it pulls in moisture, and what is left in the carburetor bowl slowly turns into a sticky varnish. The carburetor on a push mower has a main jet with a hole in it that is not much bigger than a hair. It does not take much varnish to close that hole. When the jet is blocked, the engine cannot get fuel, and no amount of pulling will change that.
The other thing that happens is the float. It is supposed to shut the fuel off when the bowl is full. Sticky fuel makes it hang up, and then you get the opposite problem: the engine floods, the plug gets wet, and it smells like gas every time you pull.
What you can try at home
Before you bring it in, three things are worth a look.
Fresh gas. If the tank has last year's fuel in it, drain what you can and put in fresh. Sometimes that is enough to wake it up.
The plug. Pull the spark plug and look at it. If it is black and wet, the engine is flooded. Let it sit a few minutes with the plug out, wipe it off, and try again.
The air filter. A filter packed with dust and grass chokes the engine. Pull it out and try starting without it. If it fires, you found it.
If none of that works, stop pulling. You are only going to hurt your shoulder.
What we do on the bench
We start with the fuel system because that is where the problem almost always is. The carburetor comes off, the bowl and the jet get cleaned or the carb gets rebuilt, the fuel line and filter get checked, and fresh fuel goes in. New plug, clean or new air filter, oil checked. Then it gets a test run under load, not just an idle in the shop.
The blade gets a look while it is here. If it is dull we will tell you, and sharpening it at the same time saves you a second trip.
Every machine gets a tag number when it comes in. We diagnose it, write the price on the tag, and call you. Nothing gets fixed until you say go.
How to keep it from happening next year
Run the mower dry at the last cut, or put fuel stabilizer in the tank and run it long enough to get treated fuel into the carburetor. Either one works. Change the oil in the fall so the engine sits in clean oil. Store it somewhere dry.
Or bring it in for winterizing and we do all of that in one visit, so the first pull in April is the only pull.
Mower will not start? Book a drop-off online, or call or text (219) 781-3814 and tell us what it is doing.