Why does my push mower shut down after 5 minutes of running?

Question

It's a little briggs and stratton, 2 years old, always had a little trouble starting, I had to (I think) open up the choke and prime it a lot then it would start and continue to run. Now it starts and then just shuts down after 5 minutes, maybe less. I leave it sit for 10 minutes and it fires back up again then shuts down.

Answer 1

first get a spark plug wrench/socket,  a can of carb cleaner run the mower till it dies then remove the spark plug, move plug wire to side, put a finger over the spark plug hole and have some one pull once on rope. U should FEEL and HEAR pressure,(dont worry keep yr hand away from blade and wire and nothing will happen during tests) if u do feel or hear pressure then reinstall plug and remove air filter and give it a quick spray into carb and if it starts its a fuel problem and if it doesn't start its an ignition problem. If u do not feel pressure while testing  wait  one hour and retest if u have pressure then u have a valve seat coming loose. To pinpoint  more exact would need to know results from above tests.

Answer 2

The engine needs a richer fuel-to air mixture when it is cold, but less fuel as it warms up. If there is too much fuel in the mix after it gets warm the engine will stall.. Ease back on the choke. As the engine gets warm, it will also heat the gas in the line, causing vapor lock (basically an air bubble in the fuel line).

As suggested above, carb cleaner can't hurt. Also, make sure the hole in the gas cap is open.

Answer 3

The small briggs engines use a diaphram type carburetor bolted directly to the gas tank.  If this is what you have, the problem is most likely the diaphram.  You will have to remove the gas tank and than remove the carb from the tank.  You can get a new diaphram and gasket for about 5 bucks at any small engine repair shop.  Make sure the carb, the pickup tube and the gas tank are clean. It is an easy job.  Note how the springs and rods hook to the carb before you remove them so they go back on for you correctly.  I have taken digital photos to be sure.

Answer 4

Make sure your air filter, oil and gas is all clean. Maintnence on a mower is key for it to last long. I would probably buy next time a funnel with a filter to put your gas in. (you can buy them at the dollar store). Like the guy said above you may have something that is clogging the gas tube. Make sure you check your oil gas and air filter. If none of these work I would bring your mower in and get it checked.

Answer 5

Maybe trash or water in the gas. As it runs, maybe the trash plugs up the pick up tube and shuts off the gas. After the engine stops the trash falls out. And then it will restart.

If you can remove the bottom of the carburetor bowl and dump it out, then replace- that may fix it.

Depending on the model- there may be just one s***w in the center that holds the bowl on. Take care to keep the gasket in place when putting it back on.