coffeesnarf
Ditto, don’t touch the mixture, if you run the engine too lean you will damage the piston.
Is it a 2-stroke or 4-stroke?
You need 3 things for your engine to run spark, gas, and air. You’re obviously getting spark and it sounds as if you may be either starving for gas or choking for air.
Replace spark plug to insure you are getting a proper spark.Does it run better?
Take the air filter off, is it wet?
Check the choke and blow out the carb. Try running the engine with the air filter and choke open. (be careful not to get anything into the carb). Does it run the same?
If not, try using a carb cleaner and fresh gas.
Ethanol fuel? It sat a while?
Drain fuel.
Add fresh fuel with a product that treats fuel for water, ethanol and adds stability. “Stabil” is one brand.
It could be that the gas cap vent is obstructed. All small engine gas caps are vented to allow air into the gas tank as fuel is consumed. If this vent is plugged fuel flow will be restricted. Loosen the gas cap and see if the engine will run smoothly. Gas caps are cheap to replace.
4-stroke, and the gas shouldn’t be ethanol - at least, no more ethanol than I put in my car (I siphon gas from my tank). I think California runs some ethanol in fuel, but as I mentioned before I’ve been running this mower for 5 years, and I don’t think it’s a fuel formulation issue.
Had the fun joy of coming down with a cold last night, so I"m putting repairs off for a few days. I’ve got a nice list now of things to check. Thanks.
Definitely sounds like bad gasoline. Winter gasoline has a higher vapor content than summer gasoline. This may have something to do with it. Drain the gas out and put fresh in and see if that fixes it.
My neighbors cheap new mower started doing the same thing. I told him to use massive doses of Stabilite gas conditioner/stabilizer till it cleared up, then keep using it from then on at a modest level.
It cleared his mower right up. And its behaved ever since. Those passages in a small carb are pretty small. It doesnt take much in the way of a varnish deposit to really mess things up. And when you are doing the last mowing of the fall, also use a large dose of stabilite in the last batch of gas then run the mower till its out of gas.
[moderating]
Since this is GQ, we’d appreciate it if you wait until some serious answers come in before you start joking and making fun of the OP’s spelling.
Thank you.
[/moderating]
It’s winter. It’s clearly in hibernation and annoyed that you woke it.
It’s threads like this that make me happy I have an electric mower.
I’m monitoring this as well as I had a similar problem with my last mower, since replaced. Putting in new gas and most of the other recommendations mentioned above had no positive effect. What was very strange about mine though was that I was mowing along fine (John Deere around 8 years old) one afternoon, bumped into a large landscape rock and all of a sudden it started the fluctuation. Weird, from reliable and trouble free to annoying as hell and nothing I tried would return it to normal operation. Rather than spend hundred(s) to fix that old of a mower, I just bought a new one (Ariens).
Does the carb sit right on top of the fuel tank? I had one like this, and there was a rubbery bladder type of gasket that was between them. After a while, usually a couple years, this bladder would get too stretched out or something and need to be replaced. I could usually tell because it would belch black smoke and run as you described until it was nearly out of fuel, then it would settle down and run closer to normal.
Good luck.
Same here. And I was really liking my new keyboard, too…
Those scofflaws preempted all my jokes.
This post has been mowed by the mowderator*
*I’m assuming the OP has got some good serious responses in this thread and won’t mind jokes now.
ahh!
doncha just love the dope!
serious answers and seriously weird, wacky, and wonderful.
i love youse all.
“Mowderator”? As in,
“Your can is LAN, and I’m the mowderator”?
Does a mowderator out rank a moderator? What about an Administrator? Does the Angel of Death outrank you all?
As to the OP: I agree with others that the issue is either your spark or the carb. Sounds like it’s starving for air.
ETA: It has been almost two weeks. Did it get fixed?
Okay, sorry I missed this thread. I repair small engines for a living. You mower is experiencing what is called a surge. It’s caused by a lean fuel mixture. Since it’s been sitting for a while, most likely the main jet is clogged with gum, or sediment. There are other causes, but this is the most likely reason. You need to take the carburetor apart and give it a thorough cleaning. This will probably solve your problem. It’s a fairly straightforward job.
If your mower has a Tecumseh engine, you may have to replace the carburetor. Craftsman used to use them exclusively. Now they have seen the light, and use a wider variety of engine manufacturers.
Briggs and Stratton, go ahead and clean it. If you feel the need to purchase a rebuild kit, check into a whole new carb. On a lot of Briggs engines, the rebuild kit costs $15, and a new one is $30.
Hope this helps, I wish I’d seen the thread sooner.
On a mower this old I have seen the governor spring break… did on mine. Check that also.
later, Tom.