Lawnmower Won't Start? Simple Method To Quickly Diagnose It!

Lawnmower Won't Start? Simple Method To Quickly Diagnose It!
If your lawnmower won't start or doesn't run properly it can be caused by various factors such as a dirty carburetor, no spark and possibly an engine with no compression!
In this video I show you a simple and easy method to diagnose a lawnmower that won't run!
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If you enjoy my small engine repair videos make sure to comment, share, thumbs up and subscribe. Thanks for watching!
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.
I do my best to teach you how to easily diagnose problems the fastest, quickest and most efficient way with real repairs beyond just replacing a spark plug. These tips are for both the homeowner and shop owner.
Whether it be a handheld, two stroke, two cycle engine like a chainsaw, weed eater, weed wacker, string trimmer, grass trimmer, line trimmer, hedge trimmer, strimmer, brush cutter, leaf blower, or four stroke, four cycle units like a lawnmower, wood splitter, lawn tractor, snowblower, pressure washer, generator or a ride on mower that needs parts installed or replaced, I’m your go-to guy.
My favorite brands of spark plugs are NGK and Champion and are the ones I recommend.
I’ve been a small engine mechanic for many decades and also run my own repair shop so my videos are loaded with tips and tricks that I have learned and want to share with you. You will also find many tool and product reviews from top brands on my channel as well.
I have the largest Small Engine Repair Video Library on KZbin and the entire internet with over 1200 videos, just GOOGLE "DONYBOY73"!
I want "DON THE SMALL ENGINE DOCTOR" on KZbin to save you time, frustration and most importantly, MONEY with my HOW-TO videos!
Due to factors beyond the control of DONYBOY73 “The Small Engine Doctor”, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. DONYBOY73 “The Small Engine Doctor” assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. DONYBOY73 “The Small Engine Doctor” recommends safe practices when working with power tools, hand tools, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of DONYBOY73 “The Small Engine Doctor”, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not DONYBOY73 “The Small Engine Doctor".
#donyboy73 #smallengine #lawnmower

[@donyboy73]

Watch m video on fixing a lawnmower that kicks back here; kzbin.info/www/bejne/fKilfnWIoJ1oaK8 Watch my video on how to fix a lawnmower that only starts with starting fluid here; kzbin.info/www/bejne/hJSuZmpjibKAfKc

[@bobbelsekwol]

I'd never argue with the king of small engines but the microswitch connected to the dead man's handle can cause no spark as well. I love your vids. Saved me hundreds in repair or renewal. Thank you donyboy.

[@jakedyer7262]

Don, i found your video on starting a flooded small engine. Thank you! Got my equipment started on a $5600 side job

[@robertoswalt319]

One of the best tips I have learned from you is that replacing the carb can save a lot of time in getting an engine running again. I keep the old carbs and repair them when I have free time so I can swap them out on relative's as they come back with issues.

[@renechaidez1416]

Thanks Dony! It works now!! I had a bent blade as well, I hit it several times until straightened, add new gas, cleaned carburator, filter, thank youagain!

[@rippubajwa]

I had the issue of mower not starting after winter. Thought i had to spend another $400. But i saw this video and used the cleaner, and it works fine now. Thankyou ❤

[@snickerstorino]

another great video, i would suggest too if someone is watching this who recently hit something with the blade you can have good spark , compression, valve adjustment and fuel but if the flywheel key sheared the timing is off and it may not run either. Pull the fly wheel and see if the key is sheared if everything else checked out, i have seen it often enough where i live.

[@raymondcampbell2346]

Thanks Don in sharing your knowledge. I too use this method to diagnose and engine.

[@carlmiller1034]

Thanks for posting. All great and simple tips to help diagnosis non-running conditions.

[@keithkilps8250]

Thanks Don for the quick tip. enjoy all of them

[@semco72057]

I have a mower with a Briggs carburetor and I will be trying that procedure on it to see if this works to start the engine. Thanks for the tip and I wish you a great new week and a more prosperous one.

[@paullemay3218]

Thank you for sharing this diagnostic information. 🇨🇦❤️

[@carlosmuler4773]

Thanks for the tip Donyboy.

[@mikezulauf8553]

thanks for the info. ,

[@r3natzyk]

Thanks so much for this video

[@aaronrossi6544]

This was fantastic. Thank you.

[@GuiyaMichung]

Great tips Dony. Thank you.

[@Webbsongs]

All the way from Finland …. Thanks Don!! Great tip!

[@markandpattyjohnson7926]

Thanks so much. Blessings to ya!

[@bobwelch5056]

Thank you

[@alexanderchuyko4889]

A very clear an simple tutorial! I have no idea what`s wrong to the engine. Carb has been cleaned, spark are tested. Compression... yes, I can feel a serious resistance when pulling the cord. But... too and too hard to start. If it starts, its only once a day :) No possibility to re-start after stopping it... Is there any particular compression needed to normal start, or if you feel a significant resistance on the starting cord, no any special compression testers are needed? Thank you

[@fredrikehne2273]

Great vid Don helped med diagnose my lawn mower just now, big thanks!

[@donyboy73]

Excellent!

[@fryreartechnology7611]

To the point and great infomation. I did this with my motorcycle too. I learned to drive around until I find a gas station with ethanol free gas or just conventional gas as it has gave me any issues since going that way. Also I top off my truck 5-6 gallons before filling my 5 gallon fuel jug too (my ocd taking over lol)

[@zed8083]

Great vid Don! Cheers!

[@shikpolam8968]

Good advice, thanks.

[@TheLawnmowerLady]

Great video! I had a guy drop off three mowers last week , all had been sitting for years. He wanted me to fix the best of the three and keep the other two for parts. This is the exact method to quickly decide the best mower to fix.

[@donyboy73]

definitely if you actually want to make money fixing them! I take deposits on lawnmowers coming in the shop

[@shsechas]

Well explained!! All your videos are always right to the point. Appreciate it.

[@donyboy73]

Glad you like them!

[@LongTimeTTFan]

Informative. Precise. Easily memorable and applicable. Thank you so much.

[@sundial6919]

Great tip for getting promptly to the problem

[@rayobas2948]

Good advice

[@jensenwilliam5434]

Thank you!!

[@deanmoore420]

Nice tip

[@lwandabikitsha7647]

Hi there I’m so thankful for your video however I want to ask when someone tilts the machine on its side and oil leaks out and flags at the corporator and all filter what do I do in that situation

[@louislandi938]

Great lesson. All instruction, no rambling on and on. Thank you!

[@donyboy73]

have a good day Louis!

[@FreedomRock44]

Thanks Dony...Good one!

[@johnhicks735]

That's helps save A lot of money to even if you half to stock up on gasket.,an jets& needle kits for them to makes things way easier.,an much simpler to.

[@sergioszczuczko6958]

Good video

[@PatriotNC1]

You mentioned that the mower was sitting over the winter. Would you recommend putting Sta-Bil in the gas tank before storage? Or just run the mower out of gas to minimize any being left in the carb? Many thanks, sir.

[@anthonygostling]

Good info

[@johnhouli3450]

Hello Don happy beginning of summer or happy spring. We’ll the snowblower is out away for the summer, it’s lawnmower time. We’ll I got it out checked oils empty as I dumped it in beginning of winter. I place new oils in and fresh gas. As I pulled the rope to start on the third pull in locked up. What could cause it to lock? I payed mower on gas side and unplugged spark plug I manually turn the belt drive and I was able to pull again but o. Third pull she locked up. Can yo much oils cause the lockup or ????

[@chrisssmallengines7163]

I also use this test but I call it , Prime for a Good Time . Checks Ignition timing , Compression , Mechanical timing , Coil or ignition modal function . It is the fastest testing that tells you the most in the shortest time . Hoo Yaa.

[@steverainey7572]

Thanks for the very good tips

[@donyboy73]

You bet!

[@rpavlik1]

Very useful! Thanks for the concise and useful video!

[@doo6211]

Your videos help save people tons of money 👍🏻👍🏻👍🏻 Can you tell me the best compression gauge to check chainsaw and weed eaters the one I have doesn’t work on them for some reason 🤔

[@donyboy73]

I have a "Lang" compression tester

[@TheRepairSpecialist]

Nice nice vid. I usually use carb cleaner in the same way. Brilliant. Thanks for sharing. 👍👍

[@donyboy73]

take care buddy!

[@steve9503]

Another common reason a lawn mower won't start is if the keyway pin that locks the pulley to the shaft is sheared or partially sheared. This can happen if you hit a hard object. This will throw off the engine timing making it impossible to start. The relatively easy fix (Tecumseh, Craftsman) is to remove the pulley and replace the keyway pin, a 50 cent part. If the pin is sheared it can make removal of the pulley challenging. You might need a 3 jaw puller to remove it.

[@user-lg4il3zr8j]

I have a Toro walk behind mower and am now trying a third carburetor which is a Kohler carb. The issue is that the mower will start but it will not rev up. I runs very slowly and then dies. Any thoughts or ideas?

[@timo9754]

Hi what does it mean if you have to spray engine spray every time to start it. Its starts first pop and runs really good but once turned off have to use engine start again

[@mishmash3446]

Great basic info to save time. Thank you!

[@donyboy73]

thanks Mish!

[@ronwatson4902]

Absolutely right. Thanks Don.

[@tyroneclarke1666]

Thank you for your professional advise Don. Your videos are always interesting. Cheers

[@donyboy73]

Thanks 👍

[@CarlJohnson-ry3gc]

THANK you!!

[@donyboy73]

You're welcome!

[@TheCrittercam001]

Don you da man!♥

[@cameronhern8305]

I have a tecumseh hm100 on a riding lawn mower, just replaced the carburetor, throttle cable is hooked up to the throttle control assembly, then linkage goes to governor arm, and another link goes to the carb butterfly, when the engine is off the throttle cable works perfectly and moves the butterfly on the carb as it should, as soon as the engine starts the engine idles at a good rpm, but the throttle cable can still move up and down but doesn’t move the linkage to the governor arm and doesn’t move the butterfly, what could be causing this?,

[@billkrause4585]

Great Vid.

[@donyboy73]

thanks Bill!

[@217Seahorse]

I used carb cleaner as it won’t start now my Murray lawn mower runs well. But I have to use the carb cleaner to start the mower each time I need the mower.?

[@lawyal]

Thank you for doing this for us. Even people living in southern hemisphere can learn from you.

[@donyboy73]

you're welcome George, greetings from Canada!

[@gnic76]

Mine decided it was only going to start with carb cleaner, then it would stay running. Took carb off and cleaned it. Nice vid and that is a nice looking rhubarb patch behind you too.

[@LudekNesnidal]

I have two Yardworks lawnmowers. Newer one will start, but only if it is cold. Once it will warm-up it will not start after again. Older one would not start even I cleaned up the carb.

[@tooljunkie6003]

Great advice!!!! Thanks again !!!

[@donyboy73]

thanks for watching!

[@frankmuschetto3385]

Don - very informative and helpful video. Practical and something easily done to quickly know if where to look next for a permanent fix. One thing I've encountered is that using starting fluid will tell you if the engine can fire however not confirm that it will run. Starting fluid is so volatile that an engine with weak, borderline compression will ignite with starting fluid but not run with gas due to low compression. I've taken to using a small squeeze bottle containing fuel and with a narrow tip which allows me to shoot a little fuel into the engine just as you did with starting fluid. If the engine fires up with the injected gas then you know there's a carb issue and that the engine likely has sufficient compression to run. Not totally fool proof but has avoided wasting time assessing a carb when the engine has internal issues.

[@kenbrown2808]

reminds me of when I was a child and a person had a car that wouldn't run. they'd hit it with ether and it would sputter a few times and die. I said, "I think it's not getting any spark." and they said, "what do you know, kid, it's firing on the ether" tow truck driver got there, stuck a screwdriver in a spark plug boot, had them turn it over and said, "there's no spark."

[@philliphall5198]

Fact is the new equipment is not saleing this year and repair shops are very busy Expect to see more than normal

[@tmurray1972]

I would like to hear about the stihl 4 mix engines, pros, cons, maintenance. And whether they’re better than the stihl commercial 2 stroke like the 94R? This just my suggestion for future videos, I like anything stihl related…lol, and all your videos anyway.👍🏻👊🏻🔧🔧🔧

[@donyboy73]

thanks, I refuse to take in most Stihl 4mix in the shop now

[@mikeguiggey2586]

@@donyboy73 are they that bad or do they run trouble free forever ?

[@tmurray1972]

@@donyboy73 Yeah, I don’t know much about them but it seems like they have a bunch of maintenance. I’ll probably buy another 2 stroke. Thinking about the 94R.

[@jessemalone8363]

4 mix requires periodic valve adjustment(easy to do if your familiar with lawn mowers), they are heavier but have much more torque than 2 strokes, iv seen them bite the dirt hard though as the cams are plastic with a thin metal back for the compression release and often times that metal breaks from the cam usually requiring a short block major engine service, also valves get out of adjustment and push rods come out. I do however own a km 91 and it has served me very well for about 4 years. Iv worked on a-lot of 2 and 4 cycle stihls and i can tell you that theres an obvious difference between a warranty , a lemon , and a unit who gets literally thrown into the back of the truck every job and sadly the last one is more and more common every day.

[@tmurray1972]

@@jessemalone8363 That’s kind of what I’ve read about them also. Thinking I’m going with another 2 banger and not have to worry about all that maintenance. Thanks for the input.

[@billkrause4585]

I wrote a quick shop troubleshooting procedure for small motors for myself using 40:1 fuel in a small oil squirt can relative to what you talked about but goes much further branching off into different repairs. I did this procedure because I'm old now and I forget. I also wrote a Journal on "Lawn and Equipment Maintenance". The recent equipment entry was when my Tractor's Steering Wheel became loose and the column dropped down. Yeah, I hit the panic button on that one, but it took walking away to learn about how to properly assemble the Column and Steering Wheel with an actual column clip this time. Yeah, the "column clip" was missing or never install during the original assembly. With the Column Clip installed the Steering Wheel can be removed and the Column will stay fixed in place without dropping. These type of problem scenarios make my hobbies of Writing Journals fun for an old guy and helps keep the brain active.

[@charlesoverton]

I can start the mower every time with the quick start and mower runs perfectly. When I released the handle I have to use quick start again. I mower the whole yard that way. Starting it with quick start.

[@stephenzies8867]

Don You Are Always A Wealth Of Information. I Enjoy All Your Videos. Same On Automobiles At least The Old Vehicles As I've Been And Auto Mechanic For 48 Years 33 At Dealers

[@donyboy73]

quick question, what would cause brake pedal to buzz or vibrate at low speed?

[@andyhamilton8940]

Use caution if you care about paint as carb cleaner will stain or possibly eat through your mowers paint.

[@justincase2281]

Fuel delivery problem on that mower for sure. Best regards.👍

[@donyboy73]

It sure is

[@fixitorstripitGardenmachines]

Great info Donny

[@donyboy73]

thanks!

[@jmaverick0807]

Hey donyboy.. I recently cleaned my generator carb and when I start it , it runs at really high RPM.. what could this problem be ? Thanks

[@johnclark7908]

Check your gaskets. You may have torn one of them or you didn't seat one of them properly

[@donyboy73]

check linkages to carburetor

[@Neighborhoodgo2guy]

Excellent explanation

[@donyboy73]

Glad you liked it

[@seanmcgillicuddy956]

Good tip .. What is the name of the plant is sitting behind the mower ?

[@donyboy73]

rhubarb

[@seanmcgillicuddy956]

@@donyboy73 Duhhh Know that you said it..

[@user-yt2vo7rv3h]

Доброго времени суток.Подскажите пожалуйста, на газонокосилке крафтсман с двигателем хонда GCV 160 при работе без нагрузки нет холостого хода,причина,с уважением ваш подписчик.

[@johnhicks735]

Dony Boy you need yourself A ultrasonic cleaner for cleaning those carburetor's out with Bud.

[@marcdehaes]

Hello Dony, I like your video's!!! But a have a favor to ask? Could you help me to find the correct clearance between the valves of my Briggs and Stratton engine? the nr on the engine is 126T02-4233-B1. Because I can't find it. Would be great appreciated. Thanks in advance.

[@kenbrown2808]

I only run ethanol free gas, and if I have a hard start, I put a splash of gas on the air filter, and it wakes it right up a lot of the time.

[@HenkElzinga]

What about brake cleaner, can I use that too?

[@donyboy73]

doesn't work good as starting fluid

[@echomax6112]

Every video is very interesting 😎👍🙋🏻‍♂️

[@donyboy73]

Thanks 👍

[@patmiller7045]

Nice rubarb.

[@donyboy73]

yes I'll have to cu some up for rhubarb pie!

[@rruizproductions]

Make sure the choke isn’t stuck.

[@Kriswixx]

spark plug, carb cleaner, and prime button usually fixes these 9/10.

[@charleseddy9903]

I have a Husquvarna 323 l string trimmer that won't start after it gets hot , what's the problem ?

[@donyboy73]

check coil

[@mikespain8655]

Carburetor cleaner is the way to go.

[@phil463]

what about timing issue?

[@cgrscott]

This spring, I had to replace my fuel pump to get my 17-year-old Cub Cadet Commercial Walk behind running again. Next year, I'll probably haver to clean the carburetor. Every spring, it's always a new problem because, I have a lot of years on this mower that I bought in 2004. I keep the engine oil changed and the grease fittings lubed up.

[@dylansawyer1419]

Which company makes the best lawn mower engines in your opinion?

[@rruizproductions]

I prefer Briggs & Stratton engines. The rest is just the carriage and blade. Portland makes a good blade.

[@donyboy73]

honda gx engines

[@user-px5no9fh4q]

Здравствуйте! Покажите пожалуйста, как настроить бензопилу Хускварну 137-142 не имея тахометра. Как Вы, правите коленвал двигателя газонокосилки?

[@jjbode1]

Попробуйте задать свой вопрос на русском языке на английском через Google Translate. Вы можете получить ответ.

[@user-px5no9fh4q]

Hello! Please tell me how to set up the Husqvarn 137-142 chainsaw without a tachometer. How do you adjust the crankshaft of a lawn mower engine when you hit a stone?

[@jjbode1]

Hey Don, the Russian fellow who commented below took my advice to Google translate his question, but he then replied to me so his question is a bit hidden. Please help.

[@KYKAYAKER274ey1]

U ever find that great carb cleaner with oil in it again

[@donyboy73]

the quaker state one, no I could never find it again!

[@gilramsey3518]

Get an electric push mower like the Kobalt 80V or a similar model. You will never go back to gas.

[@saigyl9149]

if you spray and it keeps running, then you probably have a primer/choke issue

[@DaddyBeanDaddyBean]

You skipped two important steps - does it have gas in it, and is the fuel shutoff open? My dad has overlooked the shutoff several times, ehen the starter fluid test fooled him into thinking he has a carburetor problem when the only issue is fuel can't flow from the tank to the carb.

[@999thenewman]

This method gives you answers in seconds. However, this mower has the Kohler engine, which smashes very well with a sledge.

[@donyboy73]

yes I don't like them either!

[@graydonturner]

But if it's the end of the world and you're stuck on an island alone... Kohler or Briggs and Stratton? 😉

[@davidnelson2660]

What about a dirty air filter?

[@donyboy73]

@@graydonturner briggs

[@norge696]

Nothing wrong with a kohler push mower engine. pretty much a Honda clone. Kohler Courages are a whole different story..

[@Tommyr]

Run your engine dry at the end of the season solves this problem most of the time.

[@nicolascutti9570]

Hi Dony just wondering do you repair diesel motors as well

[@donyboy73]

no i don't

[@timceltic6439]

Had the same problem spray in to carburetor and it started but stops so piston damage.

[@nlowry8]

Hey Dony, video idea. Maybe one on how to adjust the valves? That’s something you mentioned in this video

[@donyboy73]

kzbin.info/www/bejne/qGrKpWemg5p0mdU

[@dennispratt3344]

Hello from the UK great videos looking for some advice as im'e baffled with this briggs& stratton 3.5hp no start with easy start! carb on carb off new spark plug & have good spark valve clearence & timing correct & 80+ lbs compression new diaphram & gasket on carb altho showing good spark could it be going to ground just get the odd backfire through the carb when spun with a drill any suggestions please

[@mrstanskaggs1]

could be the kill switch..

[@guylaurent8138]

You could have more problems, for ex: broken key, but that's a good start...