# My lawnmower won't start **URL:** \ **Category:** Factual Questions\ **Created:** [May 3, 2016, 2:49am UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752 "2016-05-03T02:49:04Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [May 3, 2016, 3:03pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/21 "2016-05-03T15:03:19Z")
> [@Dinsdale](#): > > Mind if I toss in my lawnmower question? > > Mine requires maybe 5-7 pulls, then starts like a champ. I push and hold the priming bulb 3x like the instructions say, and then pull 3-5x. Once in a great while, it will start on the 3d or 5th pull, but I don’t expect it to. Then I push the primer another 2-3x, and pull a couple more times, and around pull 7 it starts like a champ. Once in a great while I’ll need to push the primer another couple of times. > > I don’t just lay on the primer right off the bat for fear of flooding. Plug and filter are clean. Once it starts, it will restart instantly on the first pull as I move from front to back, etc. > > Any thoughts? Yeah … I have thoughts … but I’m not allowed to post them here … My thoughts on your mower problem is emptied fuel lines … pressing the primer only sprays the carb … you still have to pull the gas through the lines before the engine will run proper. Try the primer six times and see if that helps … then try nine times and see if it works better … if you do happen to flood the thing, just pull the spark plug and let it dry out … alternately, pulling that cord that much is good for your health. My riding John Deere has an Evaporative Emission Control system that seems to just suck all the gas right out of the fuel lines. If she sits a week I have to just lay on the electric starter until she eventually starts. After just one day she starts right up. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 3, 2016, 3:06pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/22 "2016-05-03T15:06:53Z")
> [@UncleRojelio](#): > > It’s an ethanol free product. I buy it a the outdoor power store around the block but you can get it at [Home Despot](https://www.google.com/shopping/product/295546530922129457?lsf=seller:8740,store:1803379588602337217&prds=oid:11805720102459947800&q=synthetic+lawnmower+fuel&hl=en&ei=3q8oV8-6D-eRjwSpjLGwCg&lsft=cm_mmc:Shopping-_-LIAs-_-D28I-_-203571144) too. Thanks, UncleRoielio. I thought that I was the only one that called the store “Home Despot”. ---
**Author:** ![Me\_Billy](https://avatars.discourse-cdn.com/v4/letter/m/e480ec/32.png) [@Me\_Billy](https://boards.straightdope.com/u/Me_Billy)\ **Post date:** [May 3, 2016, 3:49pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/23 "2016-05-03T15:49:45Z")
Many lawnmowers no longer come with a FUEL FILTER! Then within a year, the carburetor gets clogged - Take apart and clean out the carburetor. The first thing I do when I buy a new small engine machine these days is to install my own fuel filter (if it does not have one). Inline fuel filter… [https://www.handymanhowto.com/wp-content/uploads/2009/08/DSC03371a.JPG](https://www.handymanhowto.com/wp-content/uploads/2009/08/DSC03371a.JPG) ---
**Author:** ![Kimballkid](https://avatars.discourse-cdn.com/v4/letter/k/b5a626/32.png) [@Kimballkid](https://boards.straightdope.com/u/Kimballkid)\ **Post date:** [May 3, 2016, 4:16pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/24 "2016-05-03T16:16:33Z")
^^ That’s what I was going to suggest. Check the fuel filter, if equipped. ---
**Author:** ![Dallas\_Jones](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dallas_jones/32/3277_2.png) [@Dallas\_Jones](https://boards.straightdope.com/u/Dallas_Jones)\ **Post date:** [May 3, 2016, 5:13pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/25 "2016-05-03T17:13:34Z")
Before rebuilding the carburetor check the fuel lines for cracks, especially the parts the go inside the fuel tank. Ethanol in gas causes the fuel lines to lose flexibility, harden up, and crack. That was the problem I recently fixed with my chainsaw. When I tried to pull the fuel lines out of the tank to check the filter the lines just cracked and fell apart. It would also start and run for a short time with starting fluid but just wasn’t getting fuel to the engine. Ethanol blends are the death of many small engines. ---
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [May 3, 2016, 5:37pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/26 "2016-05-03T17:37:46Z")
> [@RivkahChaya](#): > > The carburetor could have gotten out of adjustment and be running too lean. Does it try to start, then fail? you can adjust it so it runs richer, and see if that helps before you pull it and take it apart. It doesn’t try to start at all. It also doesn’t have an adjustment screw. I thought that all B&S engines had them but apparently not. ---
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [May 3, 2016, 5:42pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/27 "2016-05-03T17:42:29Z")
> [@Kimballkid](#): > > ^^ That’s what I was going to suggest. Check the fuel filter, if equipped. No fuel filter. The fuel line looks good. The carb bowl was full of gas. I just can’t tell that it’s getting anywhere from there. I’ll pull the spark plug tonight and see how it looks. I would have last night but my socket set only came with the smaller spark plug socket and of course, this is the larger one. If that doesn’t work (I’m not terribly hopeful), I’ll probably just replace the carburetor. If I spent the time cleaning and replacing seals and whatnot and it still didn’t start, I’d never know if I had done it properly. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [May 3, 2016, 6:12pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/28 "2016-05-03T18:12:24Z")
> [@Dinsdale](#): > > Mind if I toss in my lawnmower question? > > Mine requires maybe 5-7 pulls, then starts like a champ. I push and hold the priming bulb 3x like the instructions say, and then pull 3-5x. Once in a great while, it will start on the 3d or 5th pull, but I don’t expect it to. Then I push the primer another 2-3x, and pull a couple more times, and around pull 7 it starts like a champ. Once in a great while I’ll need to push the primer another couple of times. > > I don’t just lay on the primer right off the bat for fear of flooding. Plug and filter are clean. Once it starts, it will restart instantly on the first pull as I move from front to back, etc. > > Any thoughts? Hit the primer 10 times before the first pull. I suspect flooding is far from being a problem. ---
**Author:** ![Nefario](https://avatars.discourse-cdn.com/v4/letter/n/59ef9b/32.png) [@Nefario](https://boards.straightdope.com/u/Nefario)\ **Post date:** [May 3, 2016, 6:48pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/29 "2016-05-03T18:48:29Z")
> [@Dinsdale](#): > > Once in a great while, it will start on the 3d or 5th pull, but I don’t expect it to. Then I push the primer another 2-3x, and pull a couple more times, and around pull 7 it starts like a champ. Once in a great while I’ll need to push the primer another couple of times. I wonder if your primer bulb is cracked or leaky or the internal pump valve is leaky. It sounds like it needs the engine spun a few times to draw gas into the carb. ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [May 3, 2016, 7:17pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/30 "2016-05-03T19:17:54Z")
Possibly relevant anecdote. I have a Honda lawnmower that used to start on the first or second pull. Over time, it became harder to start until it got to the point where the only way I could start it was to spray starting fluid into it over and over. After _three years_ of this, it occurred to me to wonder why it was so easy to spray starter fluid into the carb when the choke was supposedly closed. It turned out that the cable had stretched and the choke was no longer working. So I had been getting it started by spraying enough starting fluid to warm the engine up enough to sputter along until it no longer need to be choked. A couple of minutes with pliers and a screwdriver and it was starting on the first or second pull again. Sometimes I’m just not a smart person. ---
**Author:** ![Dinsdale](https://avatars.discourse-cdn.com/v4/letter/d/97f17d/32.png) [@Dinsdale](https://boards.straightdope.com/u/Dinsdale)\ **Post date:** [May 3, 2016, 7:34pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/31 "2016-05-03T19:34:18Z")
Thanks all. ---
**Author:** ![Urbanredneck](https://avatars.discourse-cdn.com/v4/letter/u/ea5d25/32.png) [@Urbanredneck](https://boards.straightdope.com/u/Urbanredneck)\ **Post date:** [May 3, 2016, 7:43pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/32 "2016-05-03T19:43:18Z")
> [@excavating\_for\_a\_mind](#): > > Not so fast. The ether used in starting fluid will burn with even the slightest motivation (that is, a really weak spark). You really need to remove the sparkplug and clean it. An old toothbrush and hot soapy water is better than just ignoring it. I’ve always used a wire brush and never had a problem. A solvent like mineral spirits would be great. Just make sure it is dry and clean before your put it back. > > My guess, however, is the carburetor. Carburetors on small engines like this are usually one of two types. A diaphragm type and a bowl type. With the diaphragm type, the air cleaner/carburetor assembly typically sits on top of the gas tank. I have not had much success in repairing these. With the bowl type, there is a hose from the gas tank to the carburetor. There is a hex head fitting (it looks like a nut) under the bowl, in the center. If you remove this fitting, gas will pour out, so make sure the gas tank is empty and remove and plug the gas line before you take it off. Be careful as there are two little gaskets that like to get lost when you remove it. One between the fitting and the bowl and one between the bowl and the carburetor body. Anyway, gunk will often collect in that bowl, so removing it, cleaning it out with a paper towel and putting it back on (remembering to get the gaskets back in the right places) will often correct the problem. If you decide to use carburetor cleaner, do not get any on the gaskets. > > Oh, to replace lost or damaged gaskets, I have cut new ones out of cardboard with a pair of scissors and a sharp knife that work fine. For the bowl gasket, the thickest cardboard that is not corrugated has worked best for me. Again, a new carburetor is only around $25 so you can always just get new. ---
**Author:** ![Urbanredneck](https://avatars.discourse-cdn.com/v4/letter/u/ea5d25/32.png) [@Urbanredneck](https://boards.straightdope.com/u/Urbanredneck)\ **Post date:** [May 3, 2016, 8:01pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/33 "2016-05-03T20:01:03Z")
> [@Me\_Billy](#): > > Many lawnmowers no longer come with a FUEL FILTER! > > Then within a year, the carburetor gets clogged - Take apart and clean out the carburetor. > > The first thing I do when I buy a new small engine machine these days is to install my own fuel filter (if it does not have one). > > Inline fuel filter… > [https://www.handymanhowto.com/wp-content/uploads/2009/08/DSC03371a.JPG](https://www.handymanhowto.com/wp-content/uploads/2009/08/DSC03371a.JPG) I’m so doing this. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [May 3, 2016, 8:34pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/34 "2016-05-03T20:34:04Z")
I had a similar problem with my motorcycle every year until someone explained it to me. The evaporation of shorter-chain carbon molecules leaves a gas that smells like varnish. This is sticky. Usual “no start” is prtty simple. In the Good Old Days before fuel injection, and nowadays with small motors- The gas flows by a gas line into the carburetor bowl. There’s a float in the bowl -when the bowl is full, the float is at the top and no more gas flows into the bowl. As air sucked past the carburetor jets also sucks out gas, the level of gas in the bowl drops and the float goes down to allow more gas into the bowl. If you leave an engine sit, the gas will gunk up and stick the float where it was - in the up/no flow position. You can verify this by rapping the bottom or side of the carb bowl with a wrench or hammer. Many time, this will loosen the float enough to drop so gas starts flowing. Regular gas flow over the next few days should help dissolve enough of the gunk to make the float work properly. Or, you could clogged jet, clogged filter, deformed rubber etc as above posters mention. ---
**Author:** ![excavating\_for\_a\_mind](https://avatars.discourse-cdn.com/v4/letter/e/e8c25b/32.png) [@excavating\_for\_a\_mind](https://boards.straightdope.com/u/excavating_for_a_mind)\ **Post date:** [May 3, 2016, 9:23pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/35 "2016-05-03T21:23:26Z")
> [@Urbanredneck](#): > > Again, a new carburetor is only around $25 so you can always just get new. I wonder where you can get one at that price. I have a lawnmower with a B&S 625 series motor. I looked it up on Amazon, and with Prime, it’s $39.95. Free two-day shipping. I could have removed the bowl, cleaned it out, and put it back on in less time that it took to look the information up. After waiting two days for delivery, you still have to put it on. Removing the airfilter housing, disconnecting the throttle and other hoses (I believe there is some kind of emission stuff in there), and the two bolts that hold the carburetor to the engine (you better hope you don’t break on of those screws as the steel screws tend to get stuck in the aluminum engine block), then reversing those steps and putting the new one back on is going to take some time. Of course, with a new carb, you may have to set the mixture and idle screws. Dropping the bowl, cleaning it out, and putting it back on seems a lot easier (and cheaper) to me, but, as they say, YMMV. ---
**Author:** ![snfaulkner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snfaulkner/32/433_2.png) [@snfaulkner](https://boards.straightdope.com/u/snfaulkner)\ **Post date:** [May 3, 2016, 10:10pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/36 "2016-05-03T22:10:59Z")
> [@Dallas\_Jones](#): > > …Ethanol in gas causes the fuel lines to lose flexibility, harden up, and crack. That was the problem I recently fixed with my chainsaw. When I tried to pull the fuel lines out of the tank to check the filter the lines just cracked and fell apart. … Fixing hardened and cracking fuel lines with a chainsaw? Seems a bit of homicidal maniac type overkill, don’t ya think? I would think you could replace the lines with just a screwdriver.😉 ---
**Author:** ![smithsb](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smithsb/32/12107_2.png) [@smithsb](https://boards.straightdope.com/u/smithsb)\ **Post date:** [May 3, 2016, 11:13pm UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/37 "2016-05-03T23:13:46Z")
Same mower without the electric start; same problem after 5 years of use. Took off carb, cleaned everything I could get to, got it to start but not run beyond a few seconds. Repair place said ethanol gums up internal lines and attacks gaskets. Bought new carb, installed and no problem. Switched to non-ethanol gas. Shoot, even another 5 years would be good. Other question above. Agree that the primer bulb is likely shot, cracked, has a gasket leak. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [May 4, 2016, 12:12am UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/38 "2016-05-04T00:12:20Z")
> [@snfaulkner](#): > > I would think you could replace the lines with just a screwdriver. Won’t do any good at all, unless screwdriver is hollow. ---
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [May 4, 2016, 12:47am UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/39 "2016-05-04T00:47:30Z")
The spark plug looked practically new. A new carburetor is on its way. $31 from Amazon. ---
**Author:** ![Scumpup](https://avatars.discourse-cdn.com/v4/letter/s/ce73a5/32.png) [@Scumpup](https://boards.straightdope.com/u/Scumpup)\ **Post date:** [May 4, 2016, 1:01am UTC](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752/40 "2016-05-04T01:01:20Z")
> [@Xema](#): > > Won’t do any good at all, unless screwdriver is hollow. Screwdrivers aren’t hollow. They are full of orange juice and vodka. [Previous page](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752.md?page=1) [Next page](https://boards.straightdope.com/t/my-lawnmower-wont-start/753752.md?page=3)