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Sharpen lawn mower blade, inspect first?


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05-04-17, 04:07 AM   #1  
Sharpen lawn mower blade, inspect first?

Hi.

I've never had a lawnmower or even sharpened a blade before and was wondering. I've had a small green Lawnboy now for 3 seasons and have cut my small yard and back yard grass of course during the summer.

Well, I've never sharpened the blade. I have changed the oil though! Anyways, I just went ahead and filled the tank the other day with new gas and stabilizer mixed and forgot that I should've sharpened the blade, etc before doing that.

My mower if you tip it on it's side, even to change the oil, will spill gas. Should I just run this tank of gas out first and maybe then attempt to sharpen the blade later when the tank runs out?

Is there a way to inspect the blade and what to look for to see if it even needs sharpening? I think I have a mulching mower if that matters.

P.S. I'm sure it would cut the grass just fine, but I wouldn't really know if the grass was getting properly cut or 'ripped' or whatever.

My grass is getting long now here in Maine and I need to cut it quickly anyways. Do you think I'd hurt anything by giving it a quick trim before sharpening the blade?

 
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05-04-17, 04:23 AM   #2  
The blade should be sharpened every year. Care must be used when sharpening a blade so you don't remove more steel on one side versus the other. It doesn't have to be perfect but does need to be close. No need to fill the tank with gas before you work on it. If the tank is less than half full, spillage shouldn't be a problem.


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05-04-17, 04:52 AM   #3  
When working on a push mower I look at where the cylinder head/valve cover and carburetor is before tipping it on it's side. I try to keep the carb and the cylinder head up to help avoid spilling gas and getting oil up into the cylinder. Sometimes it's not possible to tip in the right direction. In that case I use a pair of Vice Grip pliers and pinch the fuel line leading to the carburetor. Now you can tip with the carb on the down side and only the fuel in the carburetor bowl will spill out.

 
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05-04-17, 05:03 AM   #4  
Posted By: marksr ". . . don't remove more steel on one side versus the other . . ."
Using a little inexpensive blade balancer like this can help to make sure your blade(s) are still close to balanced when you finish:
[ATTACH=CONFIG]80361[/ATTACH]
Sometimes, the dead grass weighs more than the metal that is removed !

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05-04-17, 05:11 AM   #5  
Will I kill my lawn if I don't sharpen it this year? I haven't sharpened it in seasons. My lawn is not the greatest really as it is anyways.

 
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05-04-17, 05:24 AM   #6  
It may tear the grass more than cutting it but for the most part grass is resilient. A dull or ragged blade might make the mower work harder.


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05-04-17, 05:40 AM   #7  
Push mowers are designed to be tilted in one direction, that big lever in the back of the mower that you push on to mow...???? It can also be used to tip the front of the mower up, secure the handle to the ground and you need not worry about oil or gas.
Unless you blade is bent and cutting uneven, it is not likely you would even notice a difference in sharpening it. You might notice a slight bit of difference in the load on the mower if mulching or cutting heavy grass.
Balancing is another area that is stressed too much. Yes you want it balanced however it would take an extreme amount to make any noticeable difference, even new blades are not perfectly balanced.
Tip your mower as I described, and inspect the blade for any big nicks and straightness, if it is straight and there are no big nicks, and the cutting edge is not as round as a pencil, you should be fine.


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05-04-17, 05:50 AM   #8  
For what little your using it for I'd just replace the blade.

 
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05-04-17, 07:34 AM   #9  
The most important thing when sharpening a mower blade it to remount the blade properly, it is amazing how many times they get mounted upsidedown or they are not fitted to the retainers when tightened. Have a good one. Geo

 
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05-04-17, 07:43 AM   #10  
Dull Blade

The ends of the grass will have a white, frayed appearance as below when cut with a dull blade:


 
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05-04-17, 08:07 AM   #11  
remount the blade properly, it is amazing how many times they get mounted upsidedown
I bought a new mower once that didn't cut well but I decided I'd have live with it. When it came time to change the oil and sharpen the blade I realized the blade was on upside down Turned out to be a great mower


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05-04-17, 05:15 PM   #12  
The ends of the grass will have a white, frayed appearance as below when cut with a dull blade:
[ATTACH=CONFIG]80380[/ATTACH]
Just what kind of buffalo grass is that and how tall...??? Certainly does not look like the type of grass you cut for manicured looking lawn, rather, more the type of grass you mow simply to keep it down.

I will have to tell my mowers from the Country Club and Municipal golf course that they need to bring their mowers in more than 3 yrs or when they break. Cuz by the time I see them the cutting edge is about as round as a base ball bat, and they only mention if you have time or they might need it, to sharpen or change the blades.

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05-04-17, 05:47 PM   #13  
I am not saying properly sharpened blades are not advantageous or advisable. Having blades that work properly does help with the load on the engine, mowing speed, and more so if mulching or bagging.

Deep nicks do not have to be removed as long as they have a radius to them, IE: no sharp corners. Any nicks with sharp corners, the blade should be replaced.

I should add that every spring, I get the enjoyment of watching a few of my neighbors, mostly younger males (which might explain the denying my repeated offers to help), drag out their little walmart special 100coin with a MTD powermore, or even a good ole classic briggs...fight, struggle and eventually begging for it to run and Voila!

Nice if that was the end of the story but, the end it is not.
Now armed with a grass eating monster, they proceed to logging knee high grass...(might be some) weeds, trees, falling limbs, piles among piles of rotting leaves.....etc.
This does involve several trips back to the maintenance pad, I assume because their method in attacking this knee high pasture is by raising the deck and dropping it onto each patch of knee high opposing vegetation.
Never the less they do manage to conquer the opposition, but the struggle continues....









Hope someone enjoys my rant as much as I do in real life


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05-05-17, 05:12 AM   #14  
Ok all I screwed up! I turned my Craftsman mower on it's side (forgot which one) to look at the blade, which looks OK by the way.

Now the darned thing starts and then KONKS out! So I kept starting it and it kept konking out. I realize maybe something happened with OIL AND GAS? ( ).

Anyways I waited over an hour and did manage to get it to start and run, BUT NOW it's running ROUGH of course! What should I do?

And darn now I'm at work and just realized I LEFT THE DARNED thing OUT IN THE RAIN for today here in Maine!! YIKES! Ah, ya gotta have a sense of humour in this life! lol

 
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05-05-17, 05:26 AM   #15  
CORRECTION# this is a LAWNBOY green mower! I was thinking of my Craftsman snowblower lol!

So I'm assuming fouled up the spark plug with oil?? I'm doing some long neglected research on lawnmowers and what a 4 stroke single piston engine is and how they work , etc. I love the internet!

What engine do you think my Lawnboy uses by the way?

 
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05-05-17, 06:17 AM   #16  
Posted By: Brian1900 ". . . this is a LAWNBOY green mower! . . ."
I have a Green LawnBoy (7227) and a Yellow LawnBoy (3002) and they're BOTH 2 Cycles. As a sub-division of Outboard Marine (like Evinrude and Mercury), LawnBoy's original lawnmowers were all based on Outboard Motor 2 Cycle technology.'

You want to be doubly sure that yours isn't also a 2 Cycle, and DO NOT treat it as a 4 Cycle.

 
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05-05-17, 06:31 AM   #17  
You want to be doubly sure that yours isn't also a 2 Cycle, and DO NOT treat it as a 4 Cycle.
What do you mean by that? Mixing the oil and gas? This one has separate oil and gas. I believe it's a four stoke, not a 2 cycle. It was bought at HD a couple years back for I think around $260 or something. It's a basic self propelled model.

 
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05-05-17, 06:34 AM   #18  
I believe it's basically like this one, save mine is a 2 wheel drive. I believe I also have a Kohler 149cc engine. Is that a 2 cycle?

Lawn-Boy 21 in. Variable Speed All-Wheel Drive Gas Self Propelled Mower-17739 - The Home Depot

 
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05-05-17, 06:39 AM   #19  
I have a Green LawnBoy (7227) and a Yellow LawnBoy (3002) and they're BOTH 2 Cycles. As a sub-division of Outboard Marine (like Evinrude and Mercury), LawnBoy's original lawnmowers were all based on Outboard Motor 2 Cycle technology.'

You want to be doubly sure that yours isn't also a 2 Cycle, and DO NOT treat it as a 4 Cycle.
Sorry but those mowers you have are old! Mine is a NEW Lawnboy and I don't think it's a 2 cycle. Like I said, the oil and gas are in separate dedicated compartments.

 
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05-05-17, 08:04 AM   #20  
I know all the older lawnboys were 2 cycle, I don't know about the newer ones.
You say the oil and gas are in separate compartments. Do you add oil every so often? it could be mixing it with the gas down the line. Or does it have a crankcase where you change the oil every year [or whenever]


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05-05-17, 08:25 AM   #21  
I know all the older lawnboys were 2 cycle, I don't know about the newer ones.
You say the oil and gas are in separate compartments. Do you add oil every so often? it could be mixing it with the gas down the line. Or does it have a crankcase where you change the oil every year [or whenever]
marksr. No, the oil is in a separate compartment with a dipstick. The owners manual doesn't say anything about it being a 2 cycle or mixing gas and oil. Look at the under $300 lawnboys at HD and you'll see. It's a Kohler 149cc 4 stroke.

 
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05-05-17, 09:08 AM   #22  
Posted By: Brian1900 ". . . Sorry but those mowers you have are old! . . ."
Yes, they are (1977 and 1967 respectively) . . . . I don't know what's wrong with them; they just keep on running !

With those aluminum decks and proper maintenance, they'll outlast me; they take a lick'in and keep on tick'in !

The stupid grass doesn't know the difference between whether it's being mowed by a new mower or an old mower . . . . silly grass.

 
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05-05-17, 11:13 PM   #23  
Yes, they are (1977 and 1967 respectively) . . . . I don't know what's wrong with them; they just keep on running !

With those aluminum decks and proper maintenance, they'll outlast me; they take a lick'in and keep on tick'in !

The stupid grass doesn't know the difference between whether it's being mowed by a new mower or an old mower . . . . silly grass.
I agree, the oldies were the goodies! but mine is not a 2 cycle it's a 4 stroke. I agree on keeping old things running and plan to keep mine running as long as possible. Everyone today always has to have the latest and greatest and forgot that at what time what they had was possible the lastest and greatest!

 
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05-05-17, 11:18 PM   #24  
Ok I got home and looked at the model no. It's a 10732 Lawnboy. Now I got the spark plug out and it looks black around the tip etc, but not gummy or anything and I did wipe some oil off the threads.

I actually got a new Champion spark plug at HD, but when I got home it was obviously the wrong size (the threaded part was a larger circumference).

Is the black on the plug normal? Do you think there may be oil in the chamber?

By the way I downloaded the pdf manual and it says at the end of the season to put some oil in where the spark plug goes to keep things from corroding? is this standard practice? i didn't do it the last 2 years, I hope everythings ok in there.

So what do I look for next? Should I pull the cord to see if oil spurts out?

 
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05-06-17, 03:24 AM   #25  
I did notice that the gas cap goes on real hard and has a big gouge out of it. It's had the gouge though for as long as I can remember. I don't know how it got there. Should I try running/starting it without the gas cap?

Like I said, the spark plug is black with carbon, but nothing oily or anything. I mean the carb could be clogged, but before I go through all the trouble of taking it apart and cleaning it I think I'll remove the cap and see if it runs smoother.

My latest symptom though (yesterday) is that it just starts and then conks right out.

 
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05-06-17, 03:45 AM   #26  
If I didn't have a new plug, I'd clean the old one and try again. Is the grass fresh? I've been using a lawn mower for over 50 yrs [yikes, saying that makes me feel old] and I've never bothered to oil the plug threads or put oil in the cylinder when I put the mower up for the winter.


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05-06-17, 07:36 AM   #27  
If you tilted the mower with the carb down the air filter is probably saturated with gas, remove the air filter and try to start it. Have a good one. Geo

 
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05-06-17, 07:37 AM   #28  
My latest symptom though (yesterday) is that it just starts and then conks right out
.

First thing you do is get a new plug, make sure the numbers match.

Put some SeaFoam in the gas, most auto parts stores have it.

Yesterday I fired up my lawn edger, not sure how many years since I've had it running. It would run for a few seconds then die. To keep it going I'd hit the primer once, after doing that a few times it kept running but surging. Another couple minutes of this it purred like a kitten and now starts on one pull.

Some don't like the stuff but if you have a little varnish or whatever in there it might clean it out and save you some work rebuilding the carb.

My thoughts and I'm stickin' to it.

 
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05-06-17, 07:49 AM   #29  
Is the grass fresh?
I meant to say is the gas fresh?


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05-06-17, 12:28 PM   #30  
Ok guys, I put a little fresh gas in I did get it 'running', but it's very rough. Should I put in some Seafoam?

Yes, the gas was from last September and I THOUGHT that I put stabil in it.

 
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05-06-17, 01:09 PM   #31  
StaBil gives the gas a red tint. Did you replace the plug or at least clean it?


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05-06-17, 07:20 PM   #32  
Ok, got it running beautifully again!! Whomever recommended the Seafoam, Thanks!! I did buy it, but instead I used something called "Mechanic in a Bottle". The guy at HD said "Yeah, the Seafoam is good, but try this first.

It comes in a little bottle maybe 6 inches high and it didn't have any directions or at least I didn't see any and so I just dumped the whole bottle in.

I also changed out the plug and put it a Champion plug, but didn't gap it and left it at whatever it came in the box. It looked like the same gap on the old plug. I may take it out and check it to make sure it's .30 (I think that's what it's supposed to be).

Anyways, at first it did the same things for about 8 or so pulls. It would just start (or 1/2 start) and then conk out. Then it finally started and was running, but the same roughness and I had to keep playing with the throttle bar to keep it running.

Well after a few minutes it was revving up and down and up and down and then finally conked out again, but I could see that at points during the revving up and down there would be pockets where it seemed to be smoothing out.

Well, to my amazement I restarted it and TADA, IT WAS RUNNING LIKE A TOP!!
I can't believe how well that stuff worked! Who knows something could've blown out of a gas line the more it ran, etc, but I think the stuff I put in had something to do with it!

I also went over to another HD and got some replacement air filters (blue instead of orange). I bought two, to have one on hand.

Anyways, thanks all, my Lawnboy is running great now, I can't believe it! I think next year I'm going to drain all the gas and keep it in my cellar and clean out the carb and everything when the nicer weather gets here. It's been raining all this week here in Maine.

 
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