Lawnmower Will Not Start - You Will Never Guess Why!
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- เผยแพร่เมื่อ 9 พ.ย. 2016
- Lawnmower Will Not Start - You Will Never Guess Why
Is your lawnmower hard to start or does it kickback when you try to start it? If so you may have a sheared flywheel key.
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Easy to follow and thorough step by step tutorials do it yourself (DIY) to help you with your broken lawn and garden equipment including snowblowers.
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Nice to see a video that is straight to the subject, not like a whole life story, explaining everything in their garage and a pat of a dog like most of them.
I have to hurry, i hope my mower is still out at the curb.
Lol
Lol
lol 😂
Brilliant ! You described the symptoms perfectly. My Wilko DG400 was doing exactly as you described, i checked and found the woodruff key sheared. Replaced it and started second 'easy' pull - thank you for posting this.
Thanks for your videos. I always learn from them. I've fixed my chainsaw, weedeater and lawnmower all, with your help.
You saved my Lawnmower. Just disassembled it and the key ist broken. This will be a fast and easy repair. Many thanks from me!
Hi, thank you Don for this video. I'm a heavy equipment mechanic, I have notice my lawn mower have a problem but now that I saw you video, I'm pretty sure I found what it is. Another symptom I noticed it s if you take off your air filter and you crank, there is a atomized shot of gas coming out.
You are my go to small engine information man.i think I have this symptom currently on my briggs and stratton mower. Hope your having a great day.
Great Channel. You understand youtube. No fat or fluff. No drawn out nonsense and unneeded content.
I thank you for showing up these symptoms of a bad flywheel key. Take care and I hope you have a great week.
Thank you. I have been troubleshooting my mower for days and this helped me find the solution.
You are always so good at providing detail and extra information so we understand. I never thought about a broken handle as being a signal that there may be a broken fly wheel key. Most appreciated! Great video!
Nice reminder to check for this problem before you just toss the machine. Thanks, Dony.
Thank you so much for the symptoms. After removal to check the kill switch underneath the flywheel. I believe that I incorrectly misaligned flywheel and key while reassembling.
Thanks for explaining the symptoms of a sheared flywheel key. I ran over part of the concrete curb. The mower still worked.. But the next time I tried to start it the engine made a loud backfire noise .
Sometimes I have self-doubts and your videos often fix that issue! I have the leaf blower equivalent of this issue, I think. Customer was using the blower; clothing was sucked into the machine, and it died and will not start. Has spark, has compression, has gas, etc. I wanted another opinion before I tear into this box store model because it is a pain to work on. Last year he snapped the starter rope, and the entire machine has to be disassembled to get to it.
Thank you for sharing and stay safe.
Good video. Timing is a major factor in engine performance and not many utubers will even mention it, guessing cause of the rarity of the happening. But you are right,,, hitting a sidewalk or root or obstacle that dead stops your mower especially,, can cause the key to partially or completely shear. Good information to look for and usually easy. thanks Don.
Thanks. Great quick video and if confirms suspicions I have had and will check FW keys and timing(s).
Thanks, that is exactly what is wrong with my mower. I should be able to fix that myself.Thanks again!
Excellent video and instruction donyboy! Really concise. My engine flywheel key was perfect, so I am back to the drawing board, as they say. When pulling starter cord, I still have symptoms you pointed out. I am totally puzzled now? Wonder if timing marks on cam and crank are incorrect. Connecting rod was replaced on this engine years ago. With spark plug out, engine spins easily.
I had that exact thing happen on my 7hp mower with a Briggs. Hit a piece of rusty pipe, sheared it all the way and wouldn't start at all. I managed to figure it out my self and fix it. I also noticed on my 7hp, you really have to tighten the blade bolt a lot more than on all other mowers I have.
Helpful information! Congratulations on over 101K subs. Have a good weekend!
Thanks for sharing this info. I will try to repair my (1.5 season old) PowerSmart self propelled mower.
Definitely the best info on flywheel!
Mine is doing some of your symptoms but mostly smoking (exhaust) from underneath, where the blade is, on the front left where the self propelled cover is.
It's a Toro recycler.
Any help would be awesome.
Thank you! My Briggs Intek 7hp flywheel key is partially sheered, it looks like an offset key. All of those symptoms apply. The rope snapped out of my right hand, hit my left hand and nearly broke it, instant golf ball purple bruise. Anyways, now waiting on keys to be shipped.
Thank you sir!! Awesome video and very informative!!
Maybe not a symptom, on the running of the engine, but definitely check the blade for damage and balance. And obviously oil level which I know you would do both. Great video !
This helped me to fix a problem with my car, thanks a lot.
Thanks...ur the only one that mentioned the oil from the vent tube...I was wondering where it came from.
Mine ran and sheared the tabs for the mower blade in use...then the mower after stopping could not restart due to full shear of pin.
Thanks! Great instructional video!!
Very interesting! I appreciate all these videos.
on the old Tecumseh engines they used a steel key and an aluminum flywheel and many times when the blade hit something solid the flywheel would crack right at the key way.
backfires also can occur with a partially sheared key. Loud and scary when backfires make flames come our of muffler. good diagnostic video.. Another video on replacing key would be good.
Backfiring is another symptom of a sheared key, usually happens when it kicks back while trying to start it.
Wow, my mower has all three symptoms and run like hell. I'm going to replace the key. Now I realize its such a critical part for timely firing. Thank you for sharing.
Did it work?
@@GoogleAccount-ii9sj works! the old key was bended. after replace, it starts easy and run smooth.
I hope this is the issue on my Briggs & Stratton 4.0; a couple of summers ago, I ran over a small group of thin tree branches (less than 8 inches in length)--the engine started making a slight ticking noise and small spots of oil began to appear on the deck. After I shut it down, I tried to restart it, only to be greeted by the ol' starter rope snap back! Thankfully I have a spare mower, but as soon as I can find the correct flywheel key, I will attempt this.
Very good. Three years ago my wife hit a large rock, and my lawnmower began to behave just as in your example. I just put it away and bought a new one. Now I am gonna get it ut check that shear pin
Well?
What happened when you had it checked out? Was it sheared?
Will never no lol..
I bet this is easily missed, thanks for the heads up.
What an excellent explanation. Thanks man 👍🏽
Great video, really well explained
I've got a Briggs 3.5 hp motor with a sheared key, and when trying to start it the plug fires when the intake valve is wide open and a "pop" comes out of the carb. It stands to reason that the magnet triggering the pulse into the coil isn't where it should be, due to the flywheel having rotated away from its proper position. Easy fix.
High from England don. Great vid. My qualcast cylinder mower with techumseh engine hit a clothes peg on the lawn. Now occasionally it rips the cord from my hand unless I find the compression first runs ok once started what do you think??? Cheers rob.
Nice video Donny. Only symptom I can think of that I did not hear was the burning red muffler when the key is partially sheared because the ignition is forward causing a hot run condition.
yes good one!
Thanks dony! think you solved my problem!!!
Love the videos!
Quick question...
I was given a Yazoo 26" Self Propelled mower with an 8HP Briggs commercial engine. I cleaned the carb, changed oil and plug but it only backfires when I pull the handle. No kickback. I'm at a loss. Could this be a flywheel key? Points? I'd just like s place to start as I have never encountered this. Thank you!
Hi Donboy76, really appreciate all your video has saved me a bundle! Question for you, have a v-twin Kohler Command engine. Hit a rock on the lawnmowing deck which bent the blade and broke the mandrel. Easy fix there, but engine has been "off" since the encounter. Engine starts fine, but seems to missing a bit and engine vibrates a bit (no deck engaged). Power seems lower and when I shut it down, the engine runs on sputtering for say 3 seconds before coming to a stop (always shut down promptly before). In your professional guesstimation, does this sound like a partially sheared flywheel key or a bent crankshaft (is that possible on Craftsman GT3000)? Really appreciate any feedback you could offer me!
Thankyou don :-D
Allways worth checking.
Thanks great vid good info.
Excellent! That's the problem I have! Great video
My career is over.. people will no longer put their mowers curbside for me to pick up for scrap!
Seriously though, great video, and thanks for all the info👍👍
Hey thanks Donny this sure helped a lot
thank you for sharing!!!! very good stuff! to know.
had a briggs stratton 450 148cc that had surging issues and also making occasional popping sounds while running. Tried all the usual solutions like cleaning and rebuilding the carb, even replaced governor springs, tried to adjust running speed by bending the tabs on the kill switch bracket, checkd for airleaks etc etc, nothing I did worked, eventualy decided to pull the engine apart and rebuild, when I took the flywheel off I noticed the keyway was slightly sheared and this ended up being the issue causing all my problems.
On older engines with points, if the points are driven by a flat or a cam on the crankshaft the ignition timing would not change, however the spark will be weaker or there might be no spark because the magnets in the flywheel do not pass the magneto coil at the right time. So if the flywheel key has only sheared a small amount there could be no symptoms.
I have a John Deere riding lawn mower model 125, it is powered by a Brigs and Stratton single cylinder engine . I bought it in 2009, it gave great service until this summer. It stopped running, and I found that the flywheel key was sheared. I put a new key in it and it started up, but only ran for about 3 seconds, and sheared that key. After the third sheared key I figured that it was an internal problem. After talking to some people I was told that some of those engines had a camshaft that had a nylon gear that is pressed onto the camshaft. Have you run across this problem? I plan on opening the engine case and see if this is the problem. Let me know your thoughts on this. Thanks for all of the info you pass on to us.
Thanks Donny
A great back to basics video.
Yes, I recognized this issue. Exactly what we have right now in a Briggs 7.25 HP engine of our lawn mower. It seems like ignition points are wrong. However, some people advised that it`s most likely a camshaft problem. It`s made of plastic and pretty common issue when its plastic gear wheel is getting loose on its metal axle, or a decompression mechanism is damaged. Do you have an idea how to diagnose it correctly before engine disassembly, please? Thank you
Backfiring is a common symptom of bad timing in old two-stroke scooters. I had an electric start mower my shop in a few weeks ago. Charged the battery, it turned over OK but slowly, and backfired about every 5-6 turns of engine. Pulled on the cord, and sure enough, it yanked right out of my hand. Key was nicely sheared in two.
By the way on some lawn flywheels it has instructions embossed right on the flywheel " never use steel key" or some wording like that (and even use flywheel puller). Always use an aluminum key on lawnmower flywheels or certain engines that recommend it. If in doubt check repair manual. Thing is an aluminum key cam prevent crankshaft damage or breakage in the event of the lawnmower blade wacking against a fixed object or big branch by just shearing the key. Some engines even have offset keys for ignition timing.
cool looking mower.
What about afterfire? I have a 22 inch Toro self propelled with kohler engine. Runs great although when i let go of handle to shut it off it will backfire and give almost like a clanking noise.
I have a 20 horse Intek that had a partially sheared key due to hitting an obstruction.. The main symptom was not increasing with throttle and dying. After replacing the key, it has very little improvement, slight increase in power. Is there anything else that might cause little increase in power? Also replace carb, adj. valves.
Very helpful
Was mowing with my Honda mower and went over a real thick patch of grass and the mower almost stopped and wouldn't make enough power (and smoked a little bit). Thought it was the flywheel key. Took off the cover and before I went to check the flywheel key, noticed one side of the armature/magneto/coil was touching the flywheel. Flywheel was very scraped up I readjusted the armature and the mower started right up and ran fine. Still not sure if the thick grass I tried to mow could cause this problem.
riding lawnmower D 105 brigs and straton 17.5 hp .I had 3 starters replaced as gears on starter would break after 2 day period. Would shear pin of flywheel cause that ?
Neighbor brought me his lawnmower that won't start. Blade is very loose. Told me he hit a steel pipe and mower stopped. Tomorrow's project. Great you tube channel
That is one interesting looking mower
This is exactly what is going on with my rider. I hit a rock last week and now my mower is weak. Now how do I replace this on my Briggs & Stratton vtwin.
i got a huskee mtd 173cc mower. i have to tip it on its side then pull the cord to start. then it runs great for 2 or 3 minutes then stall. put a new carb, new plug and checked the valves. something isnt adjusting right. could this be caused by a sheared flywheel key? clean gas and it flows. i am at a loss.
hi there question: i got a huskvarna lawn mower i have cleaned the carburetor, i have spark, but it won't start, it looks like it wants to start but just die what do you think it could be?
They also run like they have a slight ignition miss you can,t get to go away almost like a poping sound
2002 LT160 riding lawn mower. Hit a rock and the left blade now won’t cut and spins freely. So do I just change a shear pin? On one side?? It still starts and the right blade cuts. Do I have to re-time anything? Or just change and go.
Thank you
Top notch video
another great video
could i have a sheared flywheel key on my snowblower. I tried starting my snowblower and after a couple of tries with the electric start i heard a loud pop and now it wont start. i replaced the spark plug and the primer line do to were on the line and the spark plug is 4 years old. i have a tecumseh motor
What if its now starting after replacing the Flywheel key (im certain i put the key in properly and the slot was undamaged) But, the starter rope pulls back sometimes and sometimes smokes out the air intake when it fails to start And runs some wat weak misfiring? Timing Gear?
I just realized i put a Chinese cheapo ignition coil on it. Maybe out of line
Flywheel on my zero turn is missing teeth... it has tough spot when spinning by hand. Should i replace it?
ive got a few of the symptoms but not sure how i could have sheared it, as the engine is a gx390 clone on a golfcart so there would be nothing to hit and cause the crank to stop. it knocks on start up, it kicks backto the point it broke the teeth off the recoil but only when its cold and i dont plug the block heater in. it also back fires at cruising speeds and at shut down but only sometimes
Do magnetos go bad somehow, I hit an object and then the briggs/stratton won't start w/new coil, no spark and the the key is not sheared. I can't find a oil low cut out sw. so far.
Have you ever heard of or yourself sheared a flywheel key by using an impact gun to remove an engine pulley? yesterday I was really hammering with an impact gun on a stubborn bolt holding a pulley on. Never got it loose. But I wonder if all that impact skewed the flywheel just enough to make my engine run rough. Going to pull it apart today and see. If you think about it it's sort of impacting the crank like hitting a rock or a stump would and all the impact repeatedly might misaligned the fly wheel? On a 15 HP Briggs.
My ride on wont start all I did was take fly wheel off and put back on I 180 dgs out of timing now key looks ok
I have a Briggs and Stratto n 11 hp Riding law mower (Murray). When I turn the key to start it there's a grinding noise and the screen over the flywheel isn't spinni g. It only nudges a little. Can you help me?
Could anything else be damaged after hitting something? I removed the flywheel but the key looked ok, it may have slipped a bit downward ... I am not sure how it is positioned in the first place. I reinstalled the flywheel, and it starts now, but runs poorly and it wants to kick back when I pull the cord.
I have a Kawasaki 340 on an ultralight. It doesn't kick back but it is hard to pull to start and trouble to start. Any clue why it may be hard to pull to start?
I have a snapper rear engine rider and the pull cord shoots out while I am mowing and it screeches really bad
I can't even pull my back it raises the whole lawnmower off the ground I have to get the key put on mine hopefully it works
Donyboy.. what about a honda gcv190 pressure washer. I went to start it and it almost broke my hand.😢
This may seem like a situation for a bad key on the flywheel. But I was working in a riding mower, and it had all these symptoms. However, the key was good and straight. The problem turned out to be bad wire connections. I cleaned up the grounds, and the power wire ends on the whole machine, including start solenoid. Now the thing starts great and runs fantastic. I say this as I now have another riding mower sitting in my shop with the extra same issue. Hard crank hard start. Kick back against the starter, and occasionally, it will back fire just like the other engine on the other riding mower. OHV engines both are briggs and Stratton 17.5 hp engines. The only difference between the symptoms of a bad flywheel key and bad ground and power wire ends is that the mower when started runs great if it's a power or ground issue. And a bad key in has issues while running both may not start. So start with the key on the shaft and flywheel first. And eliminate that possibility first. Electrical wire cleaning is a long pain in the ass. As you have to clean every end positive and ground from the battery to the starter and the flywheel and coil pack and reset the coil pack to spec distance from the flywheel. A basic business card works for this.
I have a mower that flywheel key is not sheared but will only run on a prime for a few seconds. Carb is clean, I suspect the internals got out of timing with the cam and crank shaft alignment got out of sync.
you could also have a bad carburetor
mine is a twin on a ridding mower shers key when I crank it
When I pull the pull cord is keep spinning but it does not turn on the carburetor and everything is good but I don't understand what's going on but when I pull it the blade moves too so I don't know what's going on please help
Great video - i'm working on an older craftsman pushmower that runs perfectly when started. Takes a few pulls but every now and then it does jerk back after i prime the engine. New plug and blade. Could the key be sheared even if it runs perfectly? Could anything else cause this? Thanks!
I’m wondering if this is the issue I’m having with my 250 CC Honda scooter
Hi I have a husqvarna chainsaw 268XP The crankcase compression is really difficult to over come when pulling the starter cable It's so bad that as you pull the cord the chainsaw tries to pull away from your foot brace keeping the saw on the ground or as you say your fingers pulling the cord nearly get wiped of your hand I thought this to be a damaged woodruff key I had a lot of pressure on the crankshaft taper before it released the flywheel Because it was so tight to pull off I was sure the key was damaged but no its a straight as a dye Sadly I don't know what else to look at now Research just keeps coming back to damaged keyway
l have a briggs and Stratton that has ripped out the lead out of my hands......l have checked the shear key and its ok.....l have empty the sump and checked the cam and crank gears - both line up with the timing markers......so lm at a lost to why the timing is out but can't find the reason......if anyone has any suggestion it would be much appreciated -thank you
Check for bent crankshaft and or blade first
I have kick back on a 6.5 horse Tecumseh engine and the flywheel key seems to be fine. Can anything else cause this problem?
DonyBoy is a small engine Technician
I have another question. If a customer brings a mowers in with a no start problem? But his pull rope doesn't go back in, and a wheel is missing. Do you just fix the nostart problem?