What's wrong with my lawnmower?

Question

I am having trouble keeping my lawn mower running. It will start but quickly shuts down after about 2-3 seconds. Although, if I continue to push the fuel primer button it will continue to run. If I keep doing this for about 5 min, the machine seems to warm up and it will run on its' own. It almost seems like it is not getting enough fuel. I have replaced the sparkplug, cleaned the air filter and checked the oil. the next thing I will try is a fresh batch of gas. I think the gas is from last season, but I've never had a problem in the past. It is a 21" Sears push mower with a Briggs & Stratton engine (if that matters).

Has anyone dealt with this in the past? Any ideas would help. Thanks for your time.

Answer 1

In terms of small gasoline engines: I own a high quality Toro self propelled mower, a Craftsman gasoline edger, a Craftsman rototiller and a Toro snowblower. Cross my fingers I have saved a lot of headaches and $$ on tuneups by running & burning out the gasoline every fall on all my equipment. I write down & keep track of the dates when I used them last so sometimes when I didn't run out all the gasoline if the temperature reaches 50 or more in January, I will start my Toro and quickly cut the front lawn running the engine like 30 minutes or so bec I paid a premium more or less for the Toro I bought brand new when we moved into our new house like 8 years ago but it has paid for itself when I compare it to my neigbhors paying $25 to $30 every week. Back to YOUR QUESTION bec I have left old gasoline in my Rototiller bec it is used less frequently, but what worked for me was buying from Wal Mart or an auto parts store a red liquid chemical call "STA-BIL Fuel Stabilizer" manufactured by Gold Eagle? Pouring some into the gas tank of a small engine should freshen the old gasoline so enough to fire the spark and start the engine. If that doesn't work before I would look & pay a repair source via on-line in Craigslist or in the Yellow Pages under Small Engine Repair, I would remove and preferably buy a new spark plug once you remove it with a rachet set & deep socket - note there are 2 sizes for spark plugs. You might want to buy a 2nd lawnmower blade or have the one you own sharpened <= it's cheaper if you remove it yourself with a racket and socket that every Do It Yourself Homeowner should own.

Best of Luck!

Answer 2

You are absolutely right to replace the gas. I always drain my fuel out of mine at the end of the grass cutting season so that I wont have the same problem the next year. It just seems like for some reason condensation builds up over the fall and winter months. Hope this helps.

Answer 3

Inspect your fuel primer button closely. When this very same thing happened to me, I found it to be air getting into the fuel line from the aging primer button that had dried and cracked. Replacement is cheap and easy (from Sears) and the mower runs like a charm! Good luck!!!

Answer 4

Use Stabil in your fuel to keep it from going bad. You may need to take your carburetor apart and clean it up and put it back together. Be careful not to damage the gaskets. The carburetors are not that complicated on the Briggs motors. Just remember how you took it apart. Clean out the little holes that the fuel passes through with a good solvent and blow them out with compressed air.

Answer 5

Sound like the carburator needs cleaning and rebuilding. It needs to be removed, taken apart, cleaned with a good parts cleaning making sure that all passages are clear and reassembled using a repair kit. It is not a hard job but it has to be real clean. Also check the gas tank for rust and debris. Take care in the cleaning and it will run like new.

Answer 6

After about 4 months gas goes bad, so that may be it. Also check your air filter to see if it is clean.

Answer 7

Yeah, you are right, it is not getting enough fuel. You need a carb overhaul.

Answer 8

sounds like a sticking float in the carburetor