Help, please, from small-engine experts!

I am a man who was taught to take very good care of his tools, but I seem to have slipped up. My lawnmower is dying by stages. The current problems (which are related, I suspect) are as follows:

A) The ones I think I understand:

1- The thing gets way too easily clogged with grass clippings. The chute and hole seem almost to inhibit egress, and the mower chokes and dies far too frequently. I’m a conscientious mower and never have more than a half-inch to an inch or so (excluding scatterred weeds) to mow: can I stop the hole from filling up, or is this a design flaw that will necessitate a new mower?

2- The above problem is exacerbated by the fact that I live in Florida and therefore my lawn during the summer months is never completely dry or firm. Wet grass and soft ground clogs mowers faster; but so does high grass and bumpy ground, which is what you get while waiting for your lawn to dry. Any suggestions?

B) The ones I don’t understand.

3- The mower performed fine (except for the clogging problem) for a year, then began sputtering and failing to start. I cleaned the air filter, changed the oil and replaced the spark plug, all according to the manual. Problem solved, for a little while. But now the spark plug is fouling with soot almost instantly (say, 10 hours or half a dozen starts, whichever comes first). Cleaning/replacing the sparkplug/cleaning the socket solves the problem, except for the sputtering, for 3-4 starts and/or 5 hours. At this point, the air and fuel filters are spotless. Lumpy as my lawn is, the mower is set to rise above it. Oil gauge is fine, but the engine burns a little oil every now and then…

4- For the first time,yesterday, mowing a short, dry, easy lawn at a slow speed, for once with no clogging problems, fouled the blade housing.

Okay, guys: it’s a fairly powerful (6.5 hp) gas-driven push-mower. I’m not mechanically talented, but I can follow instructions if they’re clear enough. I’d appreciate any advice, even from non-lawyers (just a joke, folks!).

About the fouling of the chute.
Trun the mower over / on its side so that you can access the underside. Clean the bottom side of the deck with a stiff wire brush or screwdriver and get all the gunk (or as much as possible) off the underside. This should improve the vacuum action and get the grass clippings out without fouling.
About the engine, it is running rich. Either you have too much gas in the crankcase and the pcv is causing it to foul the plug (smell the crankcase oil, if it smells like gas, change the oil) OR your carb is running rich.
You may be able to adjust the carb, or it may need rebuilding.
Lawnmower carbs are very simple, and easy to rebuild.

WARNING!! Disconnect the spark plug before flipping the mower over! This prevents the engine from staring while your hand is in the blade.

The running rich issue may be something as simple as a bit of grit in the fuel is holding a needle valve in the carb open. Exploded diagrams of typical carbs

If the carb has a readily removed float bowl, either drain the gas tank, close the fuel shutoff valve (if any) or turn the mower so the carb is facing up. Keep in mind where the oil filler is if you tip the mower so you don’t pour out the oil by accident.

Take the bowl off (regardless of you you try to stop the fuel, some will pour out, so no smoking, please!) and check the contents - odds are good you got some dirt in there. Spray it out with carb cleaner and gently squirt some up at the needle valve. If you’re not familiar with small engine carburetors, be careful - there are small springs and parts that can be easily knocked loose and lost. Pay attention to the bolt that holds the float bowl on - there’s a tiny hole in most of them that needs to be clear.

Hopefully, that’s all that you’ll need to make things right again. You can also run some “gumout” fuel treatment through - just a tablespoon - the stuff’s usually meant to be used at the rate of one bottle for 15 gallons of gas, and your mower probably has a half-gallon tank at the most.

Finally, at the end of the mowing season, you do run it dry, right? In colder climates, I’d also advise adding Sta-Bil to the gas. Probably not necessary in Florida, but it won’t hurt.

I take it your not bagging the clippings?

Did you buy the lawnmower second hand? I’ve found that some models have a large plastic plug that goes directly in the chute to prevent grass from going in there in the first place when you use it as a mulching mower.
Some people that normally bag clippings might have thought it was just part of the packaging material and threw it away or misplaced it.

Thank you, very much, everyone.

:confused: :confused:
So just how would the rope manage to pull itself while the mower is upside down?
I’m having a bit of trouble trying to wrap my mind around this concept. :dubious:

Some mowers have electric start.

Never ever wrap your mind around an upside down mower. If that thing accidentally starts, things get ugly real fast.

In that case it would be far more important to remove the battery so that you don’t spill acid all over the mower from it being upside down. :smack:
Even if the battery were saealed, the gas pickup would now be at the top, the carb float would be at the wrong end of the float chamber. Do I need to go on? :rolleyes:

If it was this lawnmower I would remove the battery, gas tank and everything else I could think of before I went to work on it.

Never seen a pushmower with electric start, but I assume you have to turn a key or something. It’s not going to just fire up spontaneously. If you’re really worried about a young child or really stupid person trying to start an upside-down lawnmower with your hands clearly in the deck, take out the keys or disconnect the battery. I imagine a blade could give a pretty good wack just from the starter torque alone.

If I ever did see an upside down lawnmower that fired up spontanousely, I wouldn’t call a mechanic, I would call a priest.
The damn thing would have to be demonically possesed.

As any pilot or mechanic of small airplanes will tell you, if it has a blade and compression, it is dangerous. Does not need to fire to cause harm.

If you move the blade and are unlucky, it may fire if you have it in the right/wrong place. Even on an upside down lawn mower.

absolutely…it can fire from accidentaly spinning the blade.

First thing I would do is hose down the carb with the air cleaner off with a can of chem tool or other carb cleaner. it probably has a little butterfly choke thats sticking partially closed. I’d do that before tearing the carb apart.

Newer mowers it is a lot easier just to buy a carb for it and be done with it. You can find them dirt cheap some times on ebay brand new…I used to work on lawn mowers for extra money many years ago…many of the new carbs aren’t worth rebuilding.

and get a mulching blade…you wont have the chute problem near as much.

So, always disconnect the spark plug when turning over a mower.
Especially if it’s been behaving oddly.

Oh, yeah.
And “Knowing is half the battle”.


About it firing from you spinning the blade… it’s just like letting a car with a stick shift roll down hill and letting the clutch out to start it. It works… probably more dangerous when the thing’s warmed up, but never a good idea, unless you are one of those folks from TV with the amputation fetish… or maybe just feel the need to look like a pirate with the whole hook thing…

Um – guys? Guys?

It would have been easier to just buy a new one, but if a mower can have sentimental value, mine does. It’s an ancient Yazoo Master Mower, which I named (though I’m not given to naming things) after the inventor of the rotary mower. So I did my best to follow instructions. First, I got my neighbor Frank (who’s handier than I am) and then I got the mower from the Portable On-Demand Storage™ locker where I keep it and wheeled it into the garage, where I parked it next to my freezer (can’t do without it but it makes a hell of a racket, so it goes in the garage). Then I remembered I’d left the new carburetor (model number AE-35) out in the car.

While outside retrieving the AE-35 unit, I heard Frank rummaging around in the garage. “I’ll just grab your ladder and straighten it for you,” I heard my neighbor say. Who’s he talking to, I wondered. Straighten what? When I re-entered the garage, Frank and my extension ladder were gone, and the mower had been moved to the middle of the garage, well away from the freezer, next to the tandem bicycle. I put down the AE-35 unit and listened to the silence.


The freezer!

It had been unplugged. That’s weird, I thought, replacing the plug in the recepticle. Turning my attention back to the mower, I was aware that this “simple” repair job was turning into quite a different mission altogether. Then, as I reached down to uncap the spark plug, I heard a voice, quiet but quite clear and distinct, say “Don’t do that.” I straightened up and looked around. Nobody was there. Feeling more than adequately creeped out at that point, I decided to put the mower away again and go look for Frank.

Outside, I saw my ladder, fully extended, on the ground next to the PODS. “Frank!” I called. No answer. Well, he wanted the ladder for something, I thought. So I propped it against the gutter and climbed up.

Frank was prone and motionless on my roof, next to the television aerial. With a yell, I moved as lightly and quickly as I could to his side. He was dead. This was not proving to be a good day. It was hot on the roof, much too hot, and I had come outside without my hat. Dragging my neighbor back to the edge of the roof, I discovered the ladder was gone again. Disregarding the suspicious nature of these circumstances, focused only on my own survival, I remembered once yelling at my son for getting on and off the roof to retrieve a frisbee™ by climbing on the storage shed door, which swung out to a point quite near the wall of my house. To anyone who might be listening, I yelled “Open the PODS door please!” And I heard a voice, the same quiet, affectless one I had heard before, say “I’m afraid I can’t do that, Dave.” "I yelled again, protesting that my name is not, in fact, Dave, but the voice merely said “To continue this conversation would be pointless,” and was thenceforth silent.

The heck with this, I thought. If I ever get out of this, I’m going to dismantle that stupid mower piece by piece, plow up my lawn, and plant daisies or something.
Seriously, though, thanks again.

Well if you can roll a car down a hill, pop the clutch AND manage to get your hand, arm whatever in the fan you are way more clever than I am.
Also something that everyone is over looking is every mower sold in the US in recent memory (20 years?) has a blade brake and the blade won’t turn unless the blade brake lever is held down.
so for a mower that is turned on it side to start, the following would have to occur:[ul]
[li]blade brake either fails totally or is held fully off[/li][li]engine must turn far enough to energize magneto[/li][li]gas pickup must still be in liquid in carb[/li][li]mixture in cylinder must be just right for combustion[/li][li]compression must be in cyliner[/li][li]float in carb must be closed to prevent flooding[/li][li] :dubious: [/li][li] :rolleyes: [/li][/ul]
I think some of you guys are way over estimating the danger here. Me, I am more worried about a metor hitting my house. :slight_smile: