I am having a slight issue with my lawn mower.. Its a model we bought from sears 5 years ago with a 4.25 horsepower engine, no idea on the engine make but its probably a briggs& stratton. I pulled the spark plug out and it looks good and it has fuel.

What happened was I was mowing the lawn one day and it just stopped working... ok no problem it probably got too hot or something. Well the next day I try and start it and I get nothing.... I try starting it with the air filter off, nothing.

Stupid lawn mower.. I think I might just go out and buy an electric mower

Does it have spark? Pull the plug again and check. If so, try some starting fluid in the intake.

Does it have a handle you have to hold while it is running that controls the throttle? If so, take off the cover and make sure the spring hasn't come loose that holds the throttle open. I was mowing a few weeks back in a pretty rough area around some azaleas and mine stopped abruptly. I had a cracked gas tank recently, so when I bought a new one, I put on new fuel line, new plug, new oil change, good spark, and I had sprayed a half o' can of ether into the carb throat. Took the cover off, and a vine had gotten under the cover and caused the throttle spring to come off. It started on the first pull after I reattached it.

Also, when you take the air filter off, have you pumped the little primer bulb to make sure you are getting gas? If not, you may have a hole in your fuel line, it may have come off, ect....

Sincerely, JD small engine repair.

When a gas engine doesn't run it is either because you have no fuel or no spark. It is easy to verify if you have spark, as Whiskeydan suggested. Once you verify spark, then start tracing back along the fuel delivery. If you have really old gas in there and didn't use fuel stabilizer, you might have gummed up the carb or fuel line at some point.

One other thing to consider, and I don't know if your lawnmower has one, but if you have a fuel shut off valve and it somehow got nudged closed, then you won't get fuel going into the carb. I have a valve like that on my snowthrower, and I tried starting it once after forgetting I had closed the valve.

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Jonathan

2011 Mazda2
2000 E320 4Matic Wagon
1994 C280 (retired)

Nobody mentioned the flywheel key.

Ensure that your blade is tightly attached, as this can shear the key. So can hitting a rock. The engine will usually continue to run with a sheared key, but not as well as before. Once you shut it down, it will probably be impossible to start.

You may be able to determine if the flywheel is in the correct place by removing the spark plug and feeling for the compression stroke. The magnet should pass the magneto-igniter at about TDC. Of course, the only way to really be sure is to remove the flywheel nut and flywheel and take a look.

Good call...

Although, the earlier B&S engines with points wouldn't fire if the key sheared.

Problems can occur by using fuel w/ethanol

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2009 E320 Bluetec 117,000
1995 E300D 306,000 Sold
1996 Ford Taurus LX 130,000 Sold
1985 300TD Still 225,000 Sold
2016 Ford Fusion 24,900

Buy a Brill Luxus push mower, and that will solve all your problems . Right now I have been using some old rusted out reel push mower, but it still does the job good, and no exhaust fumes. Only time I used the gas push mower is when the grass is too long...

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1999 Toyota Corolla VE (Mine)
2006 Honda Odyssey (Wife's)
1979 300CD (sold)

talk about response time..

In the amount of time I was able to remove the plug, drive to Lowes, buy a plug, look at some electric lawn mowers, buy a CFL bulb and drive back you all answered and even managed to deviate from my original post

lol

I sprayed some carb cleaner in the carb and then put in the new plug..It fired up with a crap load of smoke.. But its running normal now...

If you hit something definitely check the flywheel key. Also the usual flooded / oil crudded up plug issues.

The other major problem can be if there is any dirt in the fuel bowl, it plugs up the carb. The most likely spot for this is a bolt at the bottom of the fuel bowl, 1/2" head I think that has the head at the bottom and threads going up. Pull this bolt, ( fuel will run out since the float now thinks the carb needs fuel). When you take the bolt out - have someone hold up the fuel bowl so it doesn't fall down.

In this bolt is a sideways and then vertical hole. I have heard this called the "bubbler". Any dirt in this passage way will stop the engine from running. Blow it out or use a small wire.

Good luck!

Goat.

Goats are browsers (eat shrubs) not grazers (eat grass).


Sounds like you just fouled out a plug.

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/mercedes-benz-cars-sale/296386-fs-1-owner-83-mb-300d-turbo-rebuild-parts.html

Our sears (craftsman) 5.5hp mower did the same thing last year, it started running rough suddenly and then quit and would not restart, 2 years old and always run on premium gas. Sooo....I did the usual checking of spark plug and air filter/fuel line etc...all fine, so I took the carb off....cleaned it all out and took it apart, put it all back together, adjusted the governor for some more rpms and power like the pre-Californized mowers run at....and tried again, puff of smoke and bam, was running strong and steady...in fact better than it ever had before! It must have been a dirty or clogged carb. I also switched it to Mobil 1 Turbo Diesel Truck Synthetic 5w40....runs great on it.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I have never actualy had to buy a lawn mower or trimmer, I get them during junk day and fix them. Usualy if they don't start after a few pulls the owner simply junks them. I got a nice Echo trimmer a few years back that way.

The last push mower I got looked to be a couple year old Craftsman. It must have just had bad fuel because I drained what little was left in the tank and refilled it, started right up.

Those little engines are simple, as said above first check spark than move on from their.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

My biggest gripe, is that more often than not, there is no fuel filter.
Mowing a lawn, is not exactly dust/dirt free - sooner or later, you're going to get some sort of dirt, into that fuel tank.
Maybe the guy that saved MB 2 bucks by using substandard wiring, saved the mower engine people 10 cents by foregoing a filter.

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D