Lawn Mower Won't Start (butterfly, spring, leaves, winter)

[gallagheria]

I tried using my lawn mower and it would not start. I changed the gas and the oil, and nothing happened. The engine would not start at all. I replaced the spark plug, and it still would not start. I read that if I put some gas behind the spark plug, it might help. I did remove the spark plug and poured in a little gas, and it then did start for a moment. It then shut off. I tried this several times and each time it starts and immediately shuts off--each time after I put more gas behind the spark plug. What does this sound like? Thanks.

[fred44]

When was the last time it started? Is the gas in the tank more than 6 months old? Old gas will gunk up the carburetor causing it to not start. If that's the case, drain the gas, take apart the carburetor and clean it.

[MrRational]

Originally Posted by gallagheria

I
tried using my lawn mower and it would not start.
I changed the gas and the oil, and nothing happened.
The engine would not start at all. .

Get a can of "Sea Foam Green" add some to fuel tank; splash some into carb.

Next fall get a can of Sta-Bil follow directions

[texdav]

This is a old thing. But if you have lighter fluid( always have some for goo from labels etc) ;take the spark plug out and squirt some in hole then reseat it. If its going to start it will. If not runs then stops; you have likely carb feed problem.

[gallagheria]

Originally Posted by fred44

When was the last time it started? Is the gas in the tank more than 6 months old? Old gas will gunk up the carburetor causing it to not start. If that's the case, drain the gas, take apart the carburetor and clean it.

Last fall was when I used it last. I did leave the gas in there but removed it and added new gas after it would not start. When I add gas behind the spark plug it starts for a moment and then shuts off.

[Hemlock140]

The carburetor is probably clogged with varnish, due to the old gas evaporating in it over winter. Try spraying Gumout into it through the butterfly valve (choke) take the air cleaner off, and you should see it. Let it sit 5 minutes, then try a little gas in the spark plug hole again, tighten it up quickly and try again. Repeat until it starts and stays running.

[W--Y--D]

The cheap easy fix is take the air cleaner off & pour a couple Tbl. Spoons of gas in the carb throat. Start it but watch out as it will get your attention when that gas burns. Let it run for 5 mins then replace air cleaner. Should be fine.

[LIcenter]

Since we don't know the make or model of your machine, I'm going to assume it is new enough to have a fuel bowl beneath the carburetor. What happens when you put it away, and not drain the fuel at the end of the season is, the bowl is full of fuel, and the float is in the 'shut the fuel off' position. Now as winter progresses the fuel in the bowl starts to evaporate causing moisture, and gunk. It happens at such a slow rate the float winds up getting stuck in the 'shut the fuel off' position.
What you can try first is, take the handle part of a screwdriver and give it a rap against the fuel bowl. With any luck this will free up the float allowing your new fuel in.
If this doesn't work you will need to remove the fuel bowl.
Empty the fuel tank or pinch the fuel line going to the carb to stop any gas from pouring out when the float releases. Mark the fuel bowl with a marker,so you know exactly how it goes back in. There is a deep side in the bowl that must align for the float drop.
There is a small nut/bolt at the bottom of the fuel bowl (10mm I think) Remove it. Then give a little tug on the fuel bowl to remove.

Now that the bowl is removed spray a liberal amount of carb cleaner up around the float area. After that, manually free the float by lightly jiggling it up and down a few times. (it will look like a little plastic donut) and spray some more carb cleaner up there. Spray, and clean the inside of the bowl with a clean rag, and re-install making sure not to overtighten the little bolt that holds it on. It's made of brass and will snap if you muscle it too much.
Re-fill with gas, or unpinch the fuel line, and you should be good to go.

[fisheye]

Sometimes, no matter how much you clean your carburetor; you are not going to get the goo out. Sometimes there are diaphragms that start leaking. Not all carburetors are the same or all gum deposits the same.

Many people talk about using products like StaBil to stabilize the gas from season to season. My feeling is that is not necessary or is it necessary to drain and run out all of the fuel. Of course this is my opinion and I am sure some will disagree with me. To me, from being in the business, the worse thing to do is to leave just a small amount of fuel in the tank. That leaves a larger air space and the remaining fuel evaporates and turns to gum quicker. If you top off your tank at the end of the season, I think, you can avoid these problems. StaBil is a great product and I would recommend it to people that plan on leaving equipment sit for years - like snow equipment in areas that only occasionally get snow.

As far as the OP's problem: I think that I would first try a carburetor adjustment (if it has screws to change the adjustment). It sounds as if the motor wants to run. Depending on the make and model; there could be adjusting screws. Here is a link to a B&S help page on carburetors: Adjusting the carburetor. Just be careful adjusting any carburetor because these adjusting screws have tapered points. If you close the screw too tight; you will break off the end of the screw when you attempt to loosen the screw. The reason that I first want to check the adjustment is because sometimes gum or dirt can lodge in the hole that these adjustment screws fit into. Sometimes just readjusting these screws can clear your problem. If you do manage to get the engine going; fresh fuel will help dissolve the gum deposits.

[Fox Terrier]

Last Spring, I tried to start my lawnmower.

It would not start.

After much pulling on the string, I did manage to get it started, but after a few minutes it would stop again.

In frustration (LOL) I started banging the front wheels on the ground and then tipped it over just to make sure there wasn't a string or something wrapped around the shaft of the blade.

There was nothing restricting the blade, so I banged it down on the ground again.

Lo, and behold, five baby chipmunks were laying on the deck of the mower! They were still pink!

The mother had made a nest right on top of the carburator, which I could not see under the cowling.
After I cleaned out the nest, the mower worked perfectly. It just was not getting enough air.

Sigh. I have a feeling it's going to happen again. I will soon find out.