Lawn Mower Sounds Like it's Going to Stall ( but doesn't )

Oct 12, 2009 12 Replies

Have a Craftsman gas push mower that I just bought at the beginning of this summer. Suddenly the last two times I have used it it sounds like it's going to stall although it never does. It hums along fine for a few seconds then sounds like it's about to stall then it picks up and hums along again for a few seconds, almost like clockwork. When I push down on the handle to lift the front wheels off the grass, the engine runs fine. Any ideas?


Sounds like something with the carburator. Who made the engine?

Also, maybe it is still under warranty.

Jon

Cleaned the air filter yet?

Make sure the throttle linkage is clear of debris/dirt.

DAGS for "surging" or "hunting" and small engines. B&S has a pretty good FAQ site that leads thru troubleshooting process.

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When I had that symptom it was diagnosed as a bad carb.

Between that, 2 bald front wheels, a dull blade and a broken blade mounting bracket, I opted for new.

Couldn't be happier. Honda engine with an automatic choke. Starts with one pull (or less) everytime.

Hopefully it'll do the same after being stored for it's first winter.

Careful there, it may start by just touching the pull handle. Approach with extreme caution.

Joe

The "less" refers to restarting it while it's warm. A light half-pull turns it over.

However, just to be safe, when not in use I remove the sparkplug and store it here:

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Before you do anything, put in a new plug. A plug can break down over time, but still start and run. If that dosen't fix it, then you can move on to other things like carb, timing (shear pin), valves and etc..

Hank

Usually that will cause it to pop in the muffler when it stalls, fuel builds up and fires. If it just bogs and starts up again with no pop suspect fuel problems or a governor sticking.

That's familiar to me. It often means the gas tank is nearly empty. I think the carburetor is set to run as lean as possible at normal speed. If it gets too lean and the engine slows, the governor opens the throttle, which enriches the mixture enough to prevent stalling.

If it's a bowl carburetor, I'd shut off or clamp the fuel line and unscrew the screw at the bottom of the bowl and catch the gas to see if it has water or crud. I'd make sure the jets in the screw are clear. I'd open the fuel line for a moment to see if the flow from the tank is ample and see if there is any water coming from the tank.

One is supposed to run the engine until it runs out of gas, but even that leaves some gas in the carburetor.

I'VE HAD GREAT RESULTS USING STA-BIL FOR THE LAST TWO FILL-UPS OF THE SUMMER. ONE MOWER I DIDN'T USE FOR 18 MONTHS AND IT STARTED RIGHT UP.

I would never go into winter or fall without using it.

That's exactly what my Craftsman did. It had quite a bit of water in the fuel bowl. No idea how it got there. A week earlier it had been running perfectly.

you guys are all wrong the engine or motor is probably filled with water the samething happened to me

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