Lawn mower is not happy.

[BananaDan]

Anyone know small engines? Buying a new lawn mower is just beneath frosting my hair on my priority list. I cleaned it and the carb, changed the plug, oil is good. It doesn't want to get up to speed and the RPMs are up and down. She's also exhausting white smoke. Please don't tell me the cylinder is scored.

Thoughts?

[bakerhillpins]

A stab in the dark - can you find the governor link to the carb and see if it's what is driving the RPMs up and down?

Is this the first start of the season or was it running last week?

[twodko]

Dump all the fuel and replace it with fresh.

[resq302]

Dump all the fuel and replace it with fresh.

I agree.  Sound to be either bad gas or water in the gas.  Also, is this a 2 cycle as in Lawn Boy mower or a 4 cycle mower?  The 2 cycle gas/oil mix lawn boy mowers I've used over the years were typical for doing the up and down rpm while idling until you started mowing and it was under a load which made it steady out the rpms.  If it is a 4 cycle, and the gas issue has been eliminated, I would then check for a possible issue with the governor.

[Cooter]

Also, try not to let it sit all winter with fuel in the tank/carb...This KILLS. i can't tell you how many I've had to rebuild because people are too lazy to run the fuel out of 'em.

[ITSA426]

No body's mentioned it yet but I'd scrape the grass clippings and crap off the air filter before I got too worried.

[nvrbdn]

and i know that no one does this, so it shouldnt even be mentioned, but if the oil level is too full it will really cut the performance and puff smoke.i bought a really nice almost brand new mower at a yard sale for nothing cuz it wouldnt start. emptied the oil and put in the right amount and it fired right up.

[BananaDan]

Thanks for the replies guys. It's a Yard Machines 22" push mower with a standard 3.75HP B&S motor.  The air filter is a foam style filter that is oil soaked.  It had some crud on the outer exposed areas, but I wiped the surface crud off when I cleaned everything else.  I can see a small lever that sits on top of the carb move back and forth when she's running.  It moves exactly in sync with her up/down revving.  I thought it was a choke, but maybe it's the governor?  It is linked to a white plastic lever via springs with a blade that sits right up next to the top part of the motor that spins (don't know what it's called).  I tried pinning the lever it open and she would rev up but couldn't hold it and she would start to stall.  I'm thinking it may be the gas, that's the one thing I didn't check.  I used the mower maybe 4-5 times so far this year and haven't had any problems yet.  But my backyard is getting re-done and I had my shed demo'd so for the last 1.5 years she's been living outside under my deck (some cover, but not protected).  The gas is also from last year and the can was left outside this past winter.  I usually run her dry every fall when I put her away but I didn't get to it this past fall.  When she started doing this yesterday, I had started her and cut grass for about 5-6 minutes and the tank then ran dry.  I filled her up and that's when she started performing poorly.  The reason I didn't think of the gas was I've been using this gas all spring without issues.

I'll give it a go and let you all know.  Fingers crossed.

[Hansson]

If it is one with the carb on top of the gastank change the membrane/gasket between the carb and tank. It worked for me.

[resq302]

Thanks for the replies guys. It's a Yard Machines 22" push mower with a standard 3.75HP B&S motor.  The air filter is a foam style filter that is oil soaked.  It had some crud on the outer exposed areas, but I wiped the surface crud off when I cleaned everything else.  I can see a small lever that sits on top of the carb move back and forth when she's running.  It moves exactly in sync with her up/down revving.  I thought it was a choke, but maybe it's the governor?  It is linked to a white plastic lever via springs with a blade that sits right up next to the top part of the motor that spins (don't know what it's called).  I tried pinning the lever it open and she would rev up but couldn't hold it and she would start to stall.  I'm thinking it may be the gas, that's the one thing I didn't check.  I used the mower maybe 4-5 times so far this year and haven't had any problems yet.  But my backyard is getting re-done and I had my shed demo'd so for the last 1.5 years she's been living outside under my deck (some cover, but not protected).  The gas is also from last year and the can was left outside this past winter.  I usually run her dry every fall when I put her away but I didn't get to it this past fall.  When she started doing this yesterday, I had started her and cut grass for about 5-6 minutes and the tank then ran dry.  I filled her up and that's when she started performing poorly.  The reason I didn't think of the gas was I've been using this gas all spring without issues.

I'll give it a go and let you all know.  Fingers crossed.

Dan,

That white plastic paddle looking thing IS the governor but if it does not have a good spark or combustion, the slightest dip in RPM would cause it to do what you are saying.  The fasater the wind is, the more it pushes that paddle away causing it to stay a steady RPM.  If you have an inconsistent burn or combustion, it will cause it to have a varried RPM which in turn would cause the wind to make the governor not stay out at a certain distance.  Essentially, what the governor does is act like a secondary choke inside the carburetor.  When the engine slows down, it restricts the amount of mixture going to the cylinder.  Engine starts speeding up, governor opens up more due to more wind generated by the fly wheel fins and gives more fuel mixture to the cylinder. 

Now back to if you have water in the gas or crappy gas, it could be causing it to have that erratic idle like you are saying.

[bill440rt]

Easy solution, Dan. I don't know why you didn't think of this before...
Sell me your Charger. You don't even need to get much for it. Then you'll have enough to get a new lawn mower. Heck, you might even be able to get one of them fancy-pants lawn tractors or something. Then you'd REALLY be the envy of the neighborhood! Storage problems solved, too!   

[mopar0166]

hows the carb gasket, they go bad if you dont use super instead fo regular because of the ethanol

[resq302]

Thats funny cause Ive heard if you use anything above regular gas (87 octane) you can burn out the head gasket and even melt the head due to detonation issues with the higher octane gas.  At least that is what one repair place told the customer ahead of me who had to replace his engine head and head gasket.

[BananaDan]

Easy solution, Dan. I don't know why you didn't think of this before...
Sell me your Charger. You don't even need to get much for it. Then you'll have enough to get a new lawn mower. Heck, you might even be able to get one of them fancy-pants lawn tractors or something. Then you'd REALLY be the envy of the neighborhood! Storage problems solved, too!   

Three isn't enough pal?  What would you want with my 'ol car anyway?   

[bill440rt]

Easy solution, Dan. I don't know why you didn't think of this before...
Sell me your Charger. You don't even need to get much for it. Then you'll have enough to get a new lawn mower. Heck, you might even be able to get one of them fancy-pants lawn tractors or something. Then you'd REALLY be the envy of the neighborhood! Storage problems solved, too!   

Three isn't enough pal?  What would you want with my 'ol car anyway?   

Chargers are like crack. 
C'mon. You know you want MORE!! 

[charger_fan_4ever]

Is there an line filter between the tank and carb ? My cadet zero turn has a 22hp kawasaki was running bad on the 1st mow after a few mins rpms up and down till it finally quit. Thought the battery was going dead cause it wasn't charging. Ended up the fuel filter was partly clogged. New filter and off to the races.

[bill440rt]

Dan, in all seriousness did you try the gas cap trick like we spoke about? 

[bull]

Dump that crappy ethanol gas out from the gas can into your daily driver and go get some real (zero ethanol) gas. Ever since I stopped using that ethanol crap in my mower I can store it all winter with a half a tank and it'll start on the first or second pull come spring. I used to fight that pig tooth and nail every year trying to get it to start and run right, but now I just pull the rope and start mowing.

[BananaDan]

Chargers are like crack. 
C'mon. You know you want MORE!! 

I do.  How about a trade?  I've always thought I looked good in green or purple.   

Dan, in all seriousness did you try the gas cap trick like we spoke about? 

I haven't tried a thing yet.  Between my work hours and the monsoon we've been in, it may not get looked at again until this weekend.

[BananaDan]

Dump that crappy ethanol gas out from the gas can into your daily driver and go get some real (zero ethanol) gas. Ever since I stopped using that ethanol crap in my mower I can store it all winter with a half a tank and it'll start on the first or second pull come spring. I used to fight that pig tooth and nail every year trying to get it to start and run right, but now I just pull the rope and start mowing.

It's getting harder and harder to find gas without ethanol these days, but I hear ya.

[bull]

Dump that crappy ethanol gas out from the gas can into your daily driver and go get some real (zero ethanol) gas. Ever since I stopped using that ethanol crap in my mower I can store it all winter with a half a tank and it'll start on the first or second pull come spring. I used to fight that pig tooth and nail every year trying to get it to start and run right, but now I just pull the rope and start mowing.

It's getting harder and harder to find gas without ethanol these days, but I hear ya.

I know as well as anyone living here in Hippieville. I have to drive 10 miles in any direction to get the stuff but it's either that or fight the mower for three hours.

[charger490]

like bull said find the other gas. i had a problem with my mower it would run but it would not run full speed so i took off the carb and cleaned it. still no go so i removed the exhust and there i found a spider nest cleaned it out and it runs fine now

[BananaDan]

Well fellas, I siphoned out the gas and put in fresh 89 octane and no-go.  She's still running like a stuttering dog.  I also pulled the exhaust and gave it a bit of wire brushing, no webs in there.  I'm out of ideas.  I'd go for the fuel filter as that's the only thing I haven't looked at yet but I can't for the life of me figure out where it would be, if there is one...

I don't know if this is normal or a tip to help you guys identify my problem, but I ran her for a minute without the exhaust can/muffler on and I could see detonation/flame coming out of the exhaust port. Also, the inside of the muffler can was completely black and covered with carbon as was the spark plug I pulled off last weekend when I changed it.

[Mytur Binsdirti]

Spend the big bucks and get yourself a nice Honda mower. I hate to say it, but it's the best mower I've owned.

http://powerequipment.honda.com/lawn-mowers/models/hrx217vka

[ChargersETC..ETC..]

Any chance you hit something while mowing and busted the engine crankshaft?
I have a mower with a busted crankshaft it will just barely run then all the sudden run full throttle then quits.

Another old mower I have has worn out piston rings and will foul out the spark plugs with oil and black soot but will run perfect if you only add the bare minimum of oil like just enough oil to keep the engine from seizeing up but if you add any oil it's back to fouling the spark plugs over and over so I try not to add oil to that old worn out engine .The oil will be far below the oil dip stick reading but thats the only way that engine will run.

Tip-I use plastic weedwacker line to fix broken starter recoil pull rope since it's easier then trying to thread the old broken starter rope threw the narrow recoil houseing.I just tie two weedwacker plastic lines where the old starter rope used to be and if one line unties theres still a spare plastic weedeater pull rope line in place.