Lawn Mower trouble - please help

The place for discussions about mowers, stripers, edgers, weeders, etc.
Green
Posts: 6837
Joined: September 14th, 2012, 10:53 pm
Location: CT (Zone 6B)
Grass Type: KBG, TTTF, TTPR, and FF (various mixtures)
Lawn Size: 10000-20000
Level: Experienced

Lawn Mower trouble - please help

Post by Green » June 8th, 2017, 6:58 pm

The lawn mower isn't working very well lately, and it's getting worse. The last few days, it almost doesn't turn over when starting. It's been tough starting since sometime last Fall...it would stall a bit, but then finally turn over. Now it sputters for a while, never reaches full rpm, and the cut quality is terrible, even when double mowing. The grass is tearing, not mulching well, leaving some clippings behind, and you can hear the grass tearing as it's cutting. I'd say rpm is 75% of what it should be. The lawn now has a bit of a brown cast from the poor cut quality.

The first thing I did, was to sharpen the blade about 2 weeks ago. This was before I noticed the decline in rpm. I had, however, noticed the cut quality declining. While doing this improved the cut quality slightly, it still wasn't mulching as well as it should have, and I attributed it to thick grass.

About a week ago, I started having noticeable problems starting the mower. I realized I was overdue for an oil change, so I changed the oil. I noticed a very slight improvement after a few cycles.

But then yesterday, it got really bad, and almost didn't start. I bought a replacement air filter, and changed that. The old one had debris in it. Still had trouble mowing.

I checked the spark plug, and it had a lot of residue on it, so I went to the store and bought a replacement. No real improvement after that. Doesn't run well still today.

The next thing I was thinking of trying, tonight, is to remove the engine shroud and blow everything out with the leaf blower.

After that, I was thinking of trying a carburetor cleaning solution.

The mower seems like it's almost dead. I really don't want to get stuck with it not working when there's grass to cut. As is, I have to double mow and still am not cutting with good quality.

Any advise?

Thanks.

g-man
Posts: 501
Joined: June 29th, 2016, 9:54 am
Location: Fishers, IN
Grass Type: Mix (mostly KBG)
Lawn Size: Not Specified
Level: Not Specified

Re: Lawn Mower trouble - please help

Post by g-man » June 8th, 2017, 8:31 pm

Progressively getting worst? That normally means a dirty fuel filter getting clogged. The second is the carburator getting dirty.

imauafan
Posts: 52
Joined: May 7th, 2015, 4:12 pm
Location: Huntsville, AL
Grass Type: Bermuda
Lawn Size: Not Specified
Level: Not Specified

Re: Lawn Mower trouble - please help

Post by imauafan » June 8th, 2017, 8:59 pm

A few things to try:

Replace the fuel filter if you have one.
Spray some carb cleaner in the spark plug hole as well as the air intake (remove the air filter). Let this set for awhile and then try to crank again.
Add an ounce or two of seafoam or B12 Chemtool to your fuel and run until the tank is empty.

I had a similar problem and the carb cleaner, seafoam combo has helped.

User avatar
merrimack
Posts: 26
Joined: May 15th, 2013, 6:47 pm
Location: Merrimack Valley MA (6a)
Grass Type: Midnight, Award, Bewitched KBG
Lawn Size: 10000-20000
Level: Experienced

Re: Lawn Mower trouble - please help

Post by merrimack » June 9th, 2017, 4:14 pm

I think imauafan is on the right track. I would try to rule out the fuel or fuel system. How fresh is the gas you are using? If the gas has been sitting in the can for a while, get rid of it and get some fresh gas, preferably ethanol-free gas. Drain all the fuel from the tank, and refuel with fresh gas and Seafoam. Then check the spark plug, fuel line, and filters and give it another shot.

timingchainslipped
Posts: 207
Joined: June 25th, 2016, 8:48 pm
Location: long island
Grass Type: kbg
Lawn Size: Not Specified
Level: Not Specified

Re: Lawn Mower trouble - please help

Post by timingchainslipped » June 9th, 2017, 6:56 pm

fuel or fuel system is always a good start. good move chaning the air filter and fuel filter.

spark plug gap is good? spark plug is dried, burning even, and indicates running normal (not rich nor lean)? the way it was once described to me, it should look like it was dipped in chocolate and then dried.

no vacuum leaks? (tighten all the bolts, caps, etc on anything on or going into the engine). i once solved a vacuum leak with a leaky oil cap.

more than likely your carb might just need adjustment or a rebuild (cleaning + new gaskets/floats).


Green
Posts: 6837
Joined: September 14th, 2012, 10:53 pm
Location: CT (Zone 6B)
Grass Type: KBG, TTTF, TTPR, and FF (various mixtures)
Lawn Size: 10000-20000
Level: Experienced

Re: Lawn Mower trouble - please help

Post by Green » June 9th, 2017, 9:50 pm

I blew off the engine, checked the gap on the new spark plug and adjusted it slightly. It was a bit too wide. I put a couple of ounces of Seafoam in along with the gas.

Mower still didn't run well. I was able to mow a bit, but just barely...if you could even call what I was doing walking. Also had to overlap ~50%. So it was taking about 5x longer than it should.

The second time I started it (which was after re-gapping the spark plug), it sputtered for a minute or so, and then stopped completely. First time that happened.

I was finally able to get it started again, and do more cutting with it hobbling along as before.

To answer questions:

Gas is less than a month old, not ethanol free, but always has stabilizer added before using.

I don't believe there is a fuel filter, as it's not listed in the manual.

timingchainslipped
Posts: 207
Joined: June 25th, 2016, 8:48 pm
Location: long island
Grass Type: kbg
Lawn Size: Not Specified
Level: Not Specified

Re: Lawn Mower trouble - please help

Post by timingchainslipped » June 9th, 2017, 10:48 pm

sounds to me like a carburetion issue. I'm not a big fan of sea foam unless your stuck in the ocean. I'd say have the carb serviced/rebuilt.

but if you don't want to do that and are okay with the risk, spray sea foam directly into the carb and see if that cleans anything up.

Green
Posts: 6837
Joined: September 14th, 2012, 10:53 pm
Location: CT (Zone 6B)
Grass Type: KBG, TTTF, TTPR, and FF (various mixtures)
Lawn Size: 10000-20000
Level: Experienced

Re: Lawn Mower trouble - please help

Post by Green » June 9th, 2017, 11:02 pm

Any way to do that using the liquid? I bought the liquid instead of the spray because I needed to add it to the gas as a priority.

timingchainslipped
Posts: 207
Joined: June 25th, 2016, 8:48 pm
Location: long island
Grass Type: kbg
Lawn Size: Not Specified
Level: Not Specified

Re: Lawn Mower trouble - please help

Post by timingchainslipped » June 9th, 2017, 11:05 pm

I don't think so, but really it would be wise to have it serviced.

I know people swear by sea foam but it's like chemo for the engine.

Green
Posts: 6837
Joined: September 14th, 2012, 10:53 pm
Location: CT (Zone 6B)
Grass Type: KBG, TTTF, TTPR, and FF (various mixtures)
Lawn Size: 10000-20000
Level: Experienced

Re: Lawn Mower trouble - please help

Post by Green » June 9th, 2017, 11:08 pm

Are all of these carb-cleaning chemicals bad like that?

timingchainslipped
Posts: 207
Joined: June 25th, 2016, 8:48 pm
Location: long island
Grass Type: kbg
Lawn Size: Not Specified
Level: Not Specified

Re: Lawn Mower trouble - please help

Post by timingchainslipped » June 9th, 2017, 11:11 pm

most carb cleaning chemicals are intended for hand cleaning a disassembled carb.

Green
Posts: 6837
Joined: September 14th, 2012, 10:53 pm
Location: CT (Zone 6B)
Grass Type: KBG, TTTF, TTPR, and FF (various mixtures)
Lawn Size: 10000-20000
Level: Experienced

Re: Lawn Mower trouble - please help

Post by Green » June 9th, 2017, 11:15 pm

So, they're not something that you want to add to a fuel tank proactively, then?

g-man
Posts: 501
Joined: June 29th, 2016, 9:54 am
Location: Fishers, IN
Grass Type: Mix (mostly KBG)
Lawn Size: Not Specified
Level: Not Specified

Re: Lawn Mower trouble - please help

Post by g-man » June 10th, 2017, 7:02 am

Carb problem are typically not progressive. Taking the carb apart might be the right thing, but I think gas supply needs to be ruled out. Look up your mower model on Google or YouTube for similar issues and for filter or had hose replacement. I don't recall which one it is that had a filter inside the hose from the tank. The manual doesn't call it a filter instead a hose. I'm also not a fan of seafoam.

User avatar
merrimack
Posts: 26
Joined: May 15th, 2013, 6:47 pm
Location: Merrimack Valley MA (6a)
Grass Type: Midnight, Award, Bewitched KBG
Lawn Size: 10000-20000
Level: Experienced

Re: Lawn Mower trouble - please help

Post by merrimack » June 10th, 2017, 7:41 am

Green wrote:
June 9th, 2017, 11:15 pm
So, they're not something that you want to add to a fuel tank proactively, then?
Fuel stabilizer is what you want to proactively add. To timingchainslipped's point, I wouldn't use Seafoam, or similar products, all the time. The cleaning products may help clean the carburetor a little, but removing the carburetor to clean or rebuild it is going to be the most effective. Using the cleaning products with an ultrasonic cleaner will remove any residue or buildup. Short of that, you could also try removing the carburetor bowl and emptying it to get anything floating around in there out. There are some good videos on Youtube on carburetor cleaning.

User avatar
andy10917
Posts: 29739
Joined: February 23rd, 2009, 10:48 pm
Location: NY (Lower Hudson Valley)
Grass Type: Emblem KBG (Front); Blueberry KBG Monostand (Back)
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Lawn Mower trouble - please help

Post by andy10917 » June 10th, 2017, 9:05 am

13 responses and nobody has asked the OP what kind of mower it is yet? One thing I learned through 3 college years of fixing mowers in the summer was that problems tend to repeat by mower/engine brand: "weak spots". I don't think that if the OP isn't experienced in playing with engines that telling them to disassemble the carb is high on the list of great ideas. And some chinese-crap engines have sealed carbs.

OP:

What mower and engine brand is it? How old? Has the mower ever had a tune-up?

Does the engine emit any smoke? If so, what color is the smoke, and does it only occur at startup?

Does the engine run at a steady pace right from the start, or start off well and then fade after a few seconds?

Has the engine sound become very muffled this year?

Were there any periods where the oil level was very low?

Was the onset of this problem sudden or gradual? Was everything 100% last season?

Have you inspected the underside of the mower for wrapped-up string, dried caked grass etc?

User avatar
ken-n-nancy
Posts: 2571
Joined: July 17th, 2014, 3:58 pm
Location: Bedford, NH
Grass Type: Front: KBG (Bewitched+Prosperity); Side: Bewitched KBG; Back: Fine Fescue Blend + Prosperity
Lawn Size: 10000-20000
Level: Experienced

Re: Lawn Mower trouble - please help

Post by ken-n-nancy » June 10th, 2017, 9:07 am

Sure sounds like a problem with the engine not getting fuel. Engines need just three things to run: air, fuel, and spark.

I didn't see that you mentioned the make of the engine on your mower. I have similar issues on my old el-cheapo mower with a Briggs & Stratton engine about every 2nd or 3rd year or so. My problem has always been a clogged fuel passageway in the carburetor. Usually a clogged orifice in the bowl nut, but once a different fuel passage in the carburetor (these carburetors are pretty simple - there really aren't too many places for things to go wrong.) There's no "fuel filter" on my lawn mower, so it's not uncommon for a piece of sand or something to get in there and mostly clog the passage, leading to "barely running" like you describe.

If you're mechanically handy, this really isn't a tricky thing to fix. However, if you're not mechanically savvy, you're probably better off having a shop do this or asking a mechanically inclined buddy that knows engines to come over for a meal and look at the mower with you before or after.

A pretty good set of instructions with some pictures is at Why Won't That Lawnmower Start?. (That page is a little intimidating as it is very long, but the section titled "Float Bowl Type Carburetor" has some good instructions on the steps to follow to check the float, bowl, and jet on a float bowl carburetor.) One does have to be careful when removing the float boal -- depending upon the style of the float mechanism, the float can swing lower than normal, allowing the needle portion of the needle valve to fall out if one isn't paying attention to it. (Been there, done that, got the T-shirt...)

There are also lots of youtube videos showing how to disassemble and re-assemble a lawn mower carburetor.

The orifice that typically gets clogged for me is shown in the two pictures below, which are not my photos, but come from the web page I link above:

Image
Image

User avatar
ken-n-nancy
Posts: 2571
Joined: July 17th, 2014, 3:58 pm
Location: Bedford, NH
Grass Type: Front: KBG (Bewitched+Prosperity); Side: Bewitched KBG; Back: Fine Fescue Blend + Prosperity
Lawn Size: 10000-20000
Level: Experienced

Re: Lawn Mower trouble - please help

Post by ken-n-nancy » June 10th, 2017, 9:40 am

ken-n-nancy wrote:
June 10th, 2017, 9:07 am
Sure sounds like a problem with the engine not getting fuel.
I meant to say "Sure sounds like a problem with the engine not getting sufficient fuel."

Obviously, it's getting at least some fuel, or the engine wouldn't run at all.

PS: Sorry about making a second post for this minor correction. I wanted to edit the original post to fix this, but was bitten by the edit time restriction again.

imauafan
Posts: 52
Joined: May 7th, 2015, 4:12 pm
Location: Huntsville, AL
Grass Type: Bermuda
Lawn Size: Not Specified
Level: Not Specified

Re: Lawn Mower trouble - please help

Post by imauafan » June 10th, 2017, 12:27 pm

I always start small and work my way up to bigger things. It sounds like you have done most of the basic things. I know there are different opinions on sea foam but if you try it and it works for you then that is a heckuva lot easier and cheaper than rebuilding a carburetor. My mower (Troybilt w/Honda engine) was running rough and after some research I did exactly what I specified in my previous post, I sprayed some carb cleaner in the spark plug hole and in the air intake behind the air filter. Then I added a few ounces of sea foam to the gas and cut my yard. It continued to run rough but it started to smooth out by the end of the cut which from start to finish is approximately 1 hour. It was running more smoothly than it had in several weeks so it wasn't just a coincidence. I had previous changed the spark plug and air filter which made no difference. If that does not work for you then go to the next step.

User avatar
andy10917
Posts: 29739
Joined: February 23rd, 2009, 10:48 pm
Location: NY (Lower Hudson Valley)
Grass Type: Emblem KBG (Front); Blueberry KBG Monostand (Back)
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Lawn Mower trouble - please help

Post by andy10917 » June 10th, 2017, 9:41 pm

Blue smoke indicates the presence of oil in the exhaust. Also, a very muffled exhaust can be exhaust ports slowly closed by oily exhaust carbon.

Over all, I think it's on its way out. The chinese-made Craftsman mowers really don't last that long. You might want to have a local garden center repair shop look at it, but if it were me I'd be searching for a good sale deal...

g-man
Posts: 501
Joined: June 29th, 2016, 9:54 am
Location: Fishers, IN
Grass Type: Mix (mostly KBG)
Lawn Size: Not Specified
Level: Not Specified

Re: Lawn Mower trouble - please help

Post by g-man » June 10th, 2017, 10:17 pm

^ blue smoke? Is there a post that it not approve that talks about blue smoke?

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests