Lawn Mower Won't Start

      

Dirt is the Number 1 problem with both 2- and 4-cycle lawn mower engines. This is because the engine works almost at ground level where spinning blades generate a whirlwind of dust that chokes engine air filters, fuel filters and lines, spark plugs, controls and other parts.

This 3-part article deals with lawn mowers that won't start. Even after following the directions here, you may not be able to get the mower going. This is because some symptoms are so obscure in engines that it takes a professional with professional equipment to spot the problem. But, in general, malfunctioning engines show symptoms that are easy to identify. Check the problem in an orderly fashion, as detailed below, and you usually will be able to find the solution and save a trip to the repair shop some hot, muggy Saturday morning.

PROBLEM: ENGINE WON'T START:
The procedures:

• Are the engine controls properly set on "start"?
• Does the engine have fresh fuel in the fuel tank?
• Is the tank more than half full of fuel? Is the spark plug wire attached tightly to the plug?
• Going down this checklist:

1. Trace the sheathed control cable from the handle of the equipment to the throttle on the engine. The throttle should be fully opened with the control handle setting on "start". As you move the control lever from "start" to "fast" to "stop", the cable should be clamped so that it operates the throttle. The cable can be slipping in the clamp just enough to cause the throttle to malfunction.
   Move the throttle control to its open, or "start" position with you fingers. Or, push the throttle forward, toward the front of the engine. You may have to move the control lever with your other hand to ease the throttle open. If the throttle cable is slipping in the clamp, tighten the clamp screw with a screwdriver after you push the cable forward toward the engine until the throttle stops. The throttle is now in a fully open position. Set the handle control lever on "fast" or "start" and tighten the clamp.
2. If the engine now starts, let it run several minutes. Then pull the control lever to "stop". If the engine slows but does not stop, loosen the cable clamp and pull the cable just a tad toward the control lever until the engine stops. Then tighten the clamp. Go through this sequence until the mower stops and starts on command of the control lever. No gas or dirty gas, mower manufacturers and professional lawn mower repair persons report, are two big troublemakers for engines that won't start.
   Dump out the gas in the tank in a safe spot and refill the tank—even though you think the fuel is perfectly good. If you are just starting the mowing season, start with new gasoline; last year's gas can be weak.
3. Fill the tank with fresh fuel. Low fuel in a tank sometimes can prevent starts. This sounds strange, but it is true.
4. Spark plug wires, through engine vibration, can become loose. The engine doesn't get any spark so the fuel can't be ignited.
   Pull the wire off the plug. You'll notice a thin metal "socket" which goes over the plug terminal. With pliers, carefully crimp the metal socket. Now replace the socket on the plug terminal.

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Add to: Comments (55) Toro starts but dies when self propel engaged Help - I have a 2-year-old Toro self propelled 22" that has run like a hose until last weekend. It would not start but then we got it to start but dies when you push the handle to engage the self-propelled function. As it is dying, if you pull the handle back (disengage the self-propelled function) it is revived and continues to run. Carb jet is clean, new gas, plug is good, oil, air filter all good. #55 - Danny - 08/27/2010 - 20:55 craftsman push mower wont start I have a craftman lawn mower, the pull chord won't pull. it is stuck. Please tell me what is wrong and how to fix it. #54 - Jerry Chen - 08/23/2010 - 23:35 Tipping to the left only works Troy Bilt, Briggs and Stratton 700 series 2009 - 2010. I can only start it when I lift both of the right side wheels up so its tilted. It continues to run, but when i put all 4 wheels on the ground it stops. Any reason why? I put in clean fuel and let it run for about 10 mins. still the same #53 - john - 08/14/2010 - 17:00 gas in oil i have a craftsman riding lawn tractor 17.5hp model#917.273373 gas is leaking into my oil how can i fix it #52 - scottie - 08/04/2010 - 17:45 home owner toro mower wont start! #51 - tom hidrogo - 08/03/2010 - 18:21 Craftsman mower... replaced spark plug...on pushmower, still won't start. Never had problems starting before....has gas and oil is fine! #50 - S. Koutsoubos - 08/01/2010 - 14:25 quantum mower won't start I mowed for a couple of hours, turned it off and it wouldn't start--occasionally it starts and then dies in 3 or 4 seconds. Cleaned the carb, changed air filter, and changed gas I did hit something earlier Also oil was very low--would it take off for a few seconds if I burned up the engine due to no oil? #49 - Gary Rollins - 07/30/2010 - 20:51 gravely walk behind wont start I have a gravely walk behind mower about a year old. I used the mower and put it up then a week later, cranked it up, drove it onto my trailer and when i pulled it off i went to crank it and it wont even try to start. I finally for it to start for about 2 seconds then it died. Now it wont do anything at all..i checked the spark (looks very small), i also FULLY cleaned out the carb and it still wont start. Any input on what this may be? its a kawasiki engine if that matters at all. #48 - neko - 07/22/2010 - 03:53 Riding Craftsman Mower won't start My Craftsman riding mower worked well before winter (I am in Florida). This year when I go to start it, it sounds as though it is going to start but won't "turn over". So far I replaced the battery (tested the new one and it is good) replaced coroded fuel lines (two of them), replaced two starters, the mower was on "Empty" all winter so the gas is fresh and I replaced the air filter and still the same--no difference. What should I try next? Thanks, Sarah :) #47 - Sarah - 07/12/2010 - 11:52 HELP! I have a craftman lawn mower, the pull chord won't pull. it is stuck. Please tell me what is wrong and how to fix it. Thanks, Dee #46 - Dee Dee - 07/12/2010 - 10:05 throttle cable jerks when i pull the throttle cable to start the mower it pulls back! it used to start with one fluid pull, now i get halfway thru and it jerks. what could it be. i rebuilt the carb last month, replaced the spark plug, and the oil is at the fill line. #45 - A;icia - 07/09/2010 - 10:05 mower won't start I replaced the fly key and the mower ran good for a couple times. I started mowing and it died. I had to tighten a couple bolt's and when I put the cover down and pulled the rope it wasn't turning over. Could I have put the cover on wrong so that it won't start? #44 - Chris Lanko - 07/07/2010 - 18:32 6hp b.s. no spark worked fine last week,no spark to the plug anything besides the coil to look at? thanks #43 - nick - 07/03/2010 - 21:07 engine won't prime can get my pump to prime my engine. does it need new seals or gaskets. it won't hold enough pressure to prime the pump. #42 - Bo - 07/01/2010 - 21:25 Torro mower won't start I think the air filter on my Toro is flooded, will this prevent it from starting? How do I determine if it's not a spark plug problem? There's enough gas and oil. Thanks so - Jean #41 - Jean Dailey - 06/23/2010 - 10:33 toro hello, ' My toro personal pace ran fine for a while, we changed sparkplug after needing a new one and it ran fine for a couple of times, now it runs for a while but seems like it maybe overheats and wont stay on after starting the blade. any ideas #40 - Terry - 06/20/2010 - 15:00 Starts fine when cold shutsoff after a few minutes I had the tune-up made recently. It starts at the first stry when cold but shuts off after a few minutes then will not start again. Interestingly, I never put any oil in this engine, it was always running dry, I started to have problem with it the day I added oil. It's a yard machine, probably a 93. Ran great more than 11 years without oil. #39 - Carl - 06/16/2010 - 15:55 widowed house person thank you. I crimped the metal socket and it started right off! I was ready to give up and you made my day. :) #38 - ann campbell - 06/10/2010 - 17:40 mtd wont start i changed the oil, air filter, fuel filter, fuel line. it ran fine a couple of times already this year. I can jump the starter and celenoid and it still wont start. I also changed the celenoid and the battery is fine. #37 - matt - 06/02/2010 - 20:31 wont start spray in spark plug start fires wont stay running took bowl off dirt float green clean up sprayed with blaster from lowes put gas fires wont stay running arm hurts #36 - roger schaffner - 05/29/2010 - 16:50 Poulan Pro won't start cold Poulan is 2 years old. Won't cold start after priming. Cleaned carb,fuel line and service air cleaner.Engine will run great after spraying starter fluid in carb. Don't have any ideas,could you help.Thanks great web site. #35 - Bill - 05/20/2010 - 09:34 craftman lawn mower purchased new from sears had it a few years craftman lawn mower model #143994500 want start took it for service repair shop said it needed a part called key way it would cost too much for engine labor. used it twice this summer was working great all of sudden want start. #34 - unhappy customer of sears product - 05/19/2010 - 00:18 lawnmower wont start My lawnmawer was running just fine two weeks ago. Now it wont start. I filled up the gas, oil, and cleaned the air filter. I primed it abou 10X once and it still wont start. Do you have any ideas to what might be wrong with it?? #33 - Dee - 05/15/2010 - 17:07 6.5 Craftsman Lawn mowe4r won\'t start! I had the carb cleaned and it still won\'t start. The repair man wants to chuck the engine and put a new one on the base. I just want to use my old one! When do I give it up? #32 - Sam - 05/11/2010 - 12:57 Trouble with toro lawn mower Toro Mower does not start. It will if I unscrew the Bow Drain srew My Craftsman mower does not start. But if I unscrew the Bow Drain screw located at the Float Bowl a couple of turns it stars fine but the gas will leak out. I replaced the oil,gas,spark plug and air filter. I also removed and cleaned the float bowl.I cleaned gas tank,also I put gas into spark plug hole and work\'s for a moment than stopped. I don\'t know what to do next. Thanks for you help Bob Paulson #31 - Bob Paulson - 05/08/2010 - 15:34 lawn boy 2 cycle mower the pull chord won't pull. it is stuck #30 - sheryl - 05/08/2010 - 13:31 stupid lawn mower wont start i have a mtd riding lawn mower. i have checked every thing. the motor will turn over just wont fire. just before i started working on it, it stoped randomly when i was mowing the lawn. then would not start for about an Hour. then it would start up and cut out randomly. i just finished working on it and now it wont start at all. any suggestions? thanks. #29 - brett udy. - 05/07/2010 - 00:02 Craftsman mower won\'t start Craftsman Mower does not start. It will if I unscrew the Bow Drain srew My Craftsman mower does not start. But if I unscrew the Bow Drain screw located at the Float Bowl a couple of turns it stars fine but the gas will leak out. I replaced the oil,gas,spark plug and air filter. I also removed and cleaned the float bowl.I cleaned gas tank,also I put gas into spark plug hole and work\'s for a moment than stopped. I don\'t know what to do next. Thanks for your help. David #28 - David Tapia - 05/04/2010 - 23:41 Craftsman mower chugs out A friend just gave me a barely used Craftsman push mower. They bought it new, used it twice, and stored it for 2 years (with a little fuel still in it). When I got it home, I put fresh fuel in it and it fired up with one pull. I mowed my entire yard with no problems. Now, it will fire up, cycle a couple of times and die. I've run fuel system cleaner through it, sprayed the carb with cleaner, and even sprayed the fuel lines with cleaner. No joy. Any advice? #27 - Dave - 04/28/2010 - 14:43 No gasoline to the mower I have a Quantum lawn mower which has a primer. I found that when I lay it sideways, then the primer is able to spray some gas. Standing in the normal position, no gas. In fact, standing in the normal position, it does not seem to give gas to the engine. Can anyone help? #26 - ss - 04/26/2010 - 10:43 MTD 134M679G062 will not stop when I press the Brake/Clutch I have a 1994 MTD Rider and when I'm cutting gr!@#$$ I cannot get the the mower to stop when I press the brake/clutch. It will however slow down but in the event I am about to hit or run over something I have to jerk it into Reverse since I cannot get it into Neutral. I have to cut it off if I want to stop. Also it will not start off of the key switch so I have to turn the key on and cross it over. I have already replaced the key switch. HELP HELP HELP!!! #25 - Ekytrader - 04/25/2010 - 19:13 my 6.75 craftsman will run briefly than die. what do you suggest #24 - Russ - 04/24/2010 - 20:42 mower won't start I have a used Tecumseh Centura LE 5 hp which ran great all last year. Today, first time this spring: nada. New spark plug, new gas, full oil (but last year's). Pull start after manual priming sometimes gets a sigh that sounds like it's thinking about turning over, but nothing else. Any suggestions gratefully accepted! #23 - Sue - 04/24/2010 - 17:51 Thank you Thank you Thank you!!! I want to thank you for this website. Without it I would have had to spend a lot of money to take our newly purchased used lawn mower in to get it fixed. I did exactly what you said to do with the spark plug and putting the gas in the hole. Then when it started for just a moment we then proceeded to take apart the fuel filter and clean the line. We filled it back up with new clean fuel and it started right up. I am so so so greatfull to you for posting this information. My husband and I can not thank you enough. #22 - D. Starbuck - 04/17/2010 - 17:20 Mower Start Problem I have a 6.75hp craftsman mower that will start if I spray starter fluid in carburetor but only runs for a few seconds and dies. I replaced a new carburetor and spark plug last week, but did not help. Thanks! #21 - Kevin - 04/15/2010 - 22:23 no title I have a 6.5 hp craftsman mower that will start if I spray starter fluid in carburetor but only runs for a second and dies. Soaking over night in strong carburetor cleaner does not help. There is a thin walled flexible tube that runs from the carburetor to a chamber under the flywheel. does that work like a fuel pump? Is that what makes the carburetor pull fuel into the engine? I am at wits end after working on this for 4 days and repeatedly checking all carburetor parts for clean internal components. #20 - Ray - 04/12/2010 - 08:39 mower wont start tried jumping it with truck/ mower hit and like a dummy i throttled down too quick. Could not get engine to hit again. from the posts above i am !@#$$uming the carb is the oval shaped thing to the left of the "round thing i can see spinning" when it tries to start? i have an MTD mower with Briggs and Stratton motor. thought i would try putting gas in spark plug first --the attempt to pour it over carb if the plug trick didnt work. #19 - w/o lawnmower repair man - 04/06/2010 - 21:35 weedeater mower won't start last year i ran over a water meter cover. the mower quit and blade locked up. i got the blade loosen up and cranked it up and got it started.. a couple of weeks later i got it started and mid-way into the yard it just quit... now it just won't start? #18 - rickw - 04/02/2010 - 13:54 no spark my friend was cuting gr!@#$$ last summer and she said something flew out from under it and it cut off and now it want start #17 - miss - 04/01/2010 - 22:32 You'll find a guide for troubleshooting ignition issues on My Lawn Mower Won't Start. #16 - Jon - 01/21/2010 - 07:07 if i start the lewnmower i hav to push th elittle button to inject the fuel if i stop pushing the button the lawn mower gos off #15 - michael - 10/07/2009 - 18:33 thank you! thanks to your suggestions, i didn't have to get a man to come fix my lawn mower, i did it myself...thank you!!!! #14 - DSmith - 08/22/2009 - 16:34 Craftsman Mower does not start. It will if I unscrew the Bow Drain srew My Craftsman mower does not start. But if I unscrew the Bow Drain screw located at the Float Bowl a couple of turns it stars fine but the gas will leak out. I replaced the oil,gas,spark plug and air filter. I also removed and cleaned the float bowl. I don't know what to do next. Thanks for your help. Luch #13 - Luch - 08/16/2009 - 23:45 TOO MUCH OIL... DRAINED IT... CORD WON'T PULL... Ok... have a 6 year old Tuchsumse... ran well... 1st time using it this season... over did it on the oil... drained some oil... now pull cord won't pull so I can start engine... no clue what to do... suggestions??? RT :-( #12 - RALPH - 06/23/2009 - 18:02 Lawn Tractor wont start One year old MTD w tecumseh engine. I've replaced the oil, put in fresh fuel, changed the spark plug, and swapped the battery, but still when I depress the clutch/brake, engage the choke and turn the key I get a single "click" and that's it. It wont start. Any ideas? #11 - David - 06/11/2009 - 11:34 gas leak Gas is leaking out of the carburator! How do I fix it? #10 - brandon - 06/07/2009 - 11:20 Mr. Hacker Well if your clued out about engines and or lazy - or both like me then just do this - remove the spark plug and put clean gas directly in that hole then replace the plug start the thing and go mow your lawn. When your finished your carb should be clean too! #9 - Steve O - 05/31/2009 - 17:27 Put old gas in your car's tank, with enough fuel all ready there it will be diluted enough in that big ole engine to be burned up. Way better than dumping it on the ground! #8 - Jim - 05/17/2009 - 16:26 new gas lawnmoyer wont start My moyer,I used one time.Ithan let it set in my garge for 4 yrs.I put new gas /oil in.Itried to start it ,but It wood not start,It wont even try to start.Do you have any Ideas? Thank You, Pete #7 - Peter Gr!@#$$ - 05/04/2009 - 13:53 craftsman mower please help me find info on c riding lawn mower with no spark and smart start ignition i'm not smart enough to find anything.........thanks #6 - tim - 04/20/2009 - 20:25 stuck with no spark hey i have n o spark either but there seems to be some voltage going through the plug lead as when i hold the metal end and wind over engine there is a small tingle. i have sanded rust off flywheel and have set points at 0.08, 0.010, 0.011, 0.013, 0.015 ,0.018,0.020, 0.023 inch and still no spark. i have tried these gaps with new plug and still no spark, i cut a wire which ran onto the engine and i suspected i ran to a cutoff switch from there but to no avail. there is still a wire from coil to one of the bolts holding in on which i think is a ground although it is a small wire. any ideas where im going wrong? #5 - zak - 11/16/2008 - 18:13 ouch I had a buddy spin the blade while I pulled the cord on my mower.I started alright however he lost his hand.Pissed me off because I had to shut the thing off an call 911.And the worse part was after the carted him away I tried to restart the mower an it wound not start.Rat fart!!!!!!!! #4 - Brian - 08/10/2008 - 07:59 Self Propelled :-( My toro self propelled lawn mower has been great but all of a sudden the self propelled feature on it does not work. I am a single mother and don't have the money to take it into the shop. I am way good at fixing things I just don't know where to start with this Any ideas #3 - Camogirl - 07/28/2008 - 19:24 I cannot believe this page encourages readers to "Dump out the gas in the tank in a safe spot and refill the tank". Not only does dumping do lasting, serious damage to the local soil and seep into YOUR drinking water, it is almost universally illegal. Please dispose of gasoline properly!! #2 - John - 03/27/2008 - 15:31 Check the air too As well as fuel and a spark you engine needs air too. Make sure your air filter is not clogged with dirt or gr!@#$$. #1 - mower air intake - 10/30/2007 - 01:41 Name E-mail (Will not appear online) Title Comment To prevent automated Bots form spamming, please enter the text you see in the image below in the appropriate input box. Your comment will only be submitted if the strings match. 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