# Lawn mower starts then dies



## Mark Harvey (Apr 20, 2009)

*lawn mower*

Hard to say but here are some ideas. If gas has been in the machine for a long time, it creates a film that can prevent a good flow. This usually corrects itself once you've run the machine for a while ... flushing out the old stuff. Check the fuel line to make sure it's not kinked or blocked. (Disconnect it and see if the gas flows freely). The fuel filter could be faulty. It's fairly cheap so I would simply replace it. The carburetor is usually pre-set and shouldn't need any adjusting. Lastly, the fuel itself may be dirty or have water in it. Drain the tank and start with fresh gas.
Hope this helps, good luck.


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## gazz87 (Nov 17, 2011)

*Re:*

Thanks Mark... Should I be mixing anything with the gas?? I dont have to mix oil with it because there is a separate tank for the oil. I just put fresh gas in the tank... Before I did, I disconnected the gas line, theres no kinks in it and nothing blocking the flow :\ Do you think I need a new filter?


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## dougp23 (Sep 20, 2011)

Occasionally when I have a mower that's temperamental like that, I add a bit of drygas to the gas. Just a bit, since the engine and tank are so small.
If you're going to store it for an extended period, add some Stable to the gas.
As a start, yep, I would replace that gas filter. They gum up pretty quick.


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## Mark Harvey (Apr 20, 2009)

*lawn mower*

Gazz, I'd do the filter, ... as mentioned, things can gum up quite quickly ... usually because the machine isn't used on a regular basis. Again, keep in mind that dirt an water can also cause peoblems. If you wash off the mower, try to avoid getting water near the gas tank fill area.


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## JoJo-Arch (Sep 15, 2011)

Is it a four stroke or two stroke?. Asuming it's a four stroke The oil sits in the crankcase, and you don't add oil to the mix. You put standard or normal petrol in the petrol tank. The problem can be either petrol related or ignition related. Always do the easy checks first. Ignition, remove the spark plug and wedge to the metal frame, well away from the cylinder hole it screws into. If you can't find a suitable place get a single insulated wire lead and bare about 1'' from each end. Attach one end to a bolt or screw on the frame and wrap the other bare end around the body of the plug, near the treaded end. Clip the high tension lead onto the nut at the end of the plug, making sure the nut is tight on the plug. Pull the start cord as rapidly as you can. The engine will turn easily without the plug in place. You should see a fat blue spark about five times or so and hear a crackle with each spark. No spark means no ignition. Next the spark plug itself could be cracked inside and making poor contact, so change the plug for a new one and repeat above. If you get sparking, that was the problem, if not, you go to stage 2. This involves removing the cowl and flywheel and may void your warranty, so if you are not getting a good spark, take the machine to the dealer and demand repairs or a new one under warranty, before removing the flywheel. Suppose, you did get a good and regular spark its time to check the timing. put your finger just inside the plughole and very very gently turn the flywheel by hand. At the point you just feel the piston touch your finger and you are in the compression stroke (every 4th rotation), the spark should go off. If it goes off any other time, the timing could be out of phase, though with a single cylinder this is hard to do.

Moving on to petrol, it stands to reason the petrol should be clean and fresh. If you see a water bubble as the petrol floats on water, your fuel is contaminated. Water contained in petrol (a natural component) stored in a metal can left out in the cold can condense out of the petrol and goes to the bottom of the can. If this petrol is shaken up, the water doesn't re-enter the petrol but stays in suspension as tiny bubbles of water. These bubbles eventually fuse together and you get the condensate (water) separating from the petrol. Thus when you first crank the engine, it will propably start, until the first bubble of water kills the spark plug and the engine stops. It doen't run on water as water is uncombustible. If the engine splutters or back fires, the presence of water in the fuel is the first suspect. If it's a hot day and after several starts, the engine runs well after it warmed up, this means the engine is hot enough to evaporate the water and from this point will keep running, provided there are only a few droplets of water. if you leave the mower for a while and find it hard to start when the engine has cooled, this confirms the problem is water in the fuel.

These simple tests may be all that's needed. Beyond this, if the problem persists, it will require a technician to do more invasive tests. If you try these yourself you can easily void your warranty or severly damage the engine. Take it back to the dealer if you reach this point and demand your warranty rights.


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## HARRY304E (Nov 18, 2011)

gazz87 said:


> Hi everyone... First off, I just want to say that I am not savvy when it comes to this stuff but I need some help. I have a Yard Machines Push-Mower (158cc I believe) that I bought from Home Depot about a year ago. I have used it several times and always had trouble starting it, but I always eventually got it to start and stay on. Now, it won't start at all. I push the prime button, pull the cord, then it dies in about less than five seconds. The only way it will actually stay running is if I constantly push the prime button while it is running (which is impossible to do in order to push the mower). I went to Home Depot, they told me that I possibly needed a new filter but I told them that the mower is practically brand new. So, they told me to clean the filter by soaking it in gas, squeezing out the gas and then let it air dry... so I did. I also put new gas in the mower, and took apart the carb. The carb was perfectly clean considering I used the mower only a handfull of times. I have no idea what else to do or how to get it started. I can't return/exchange it because it is past their 30 day policy.


Check and see if it has a Choke and run setting that is what it sounds like to me.

Also use 89 octane Gasoline i use that for my machines.


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## 95025 (Nov 14, 2010)

You've got a fuel-supply problem. What the kid at HD is guessing at is almost certainly _not_ correct. Your air filter does not need to be soaked in gas and wrung out.

1. It is possible that the orifice in the carb, that sends fuel into the engine, is partially plugged. That can be the result of a tiny speck of dust, partial blade of grass and/or gummed up gas. The only way you're going to get it cleared out is if you have some carb-cleaner, and know which areas to blow it through. This primary orifice will be on the "stem" at the bottom of the carb, where is sucks gas out of the bottom of the carb bowl.

2. It is possible that the carb float is not working correctly, and not allowing enough gas into the carb bowl to provide fuel for the engine. This is highly unlikely, but the fix is to bend the tang that presses against the needle valve to close it. It is also possible that the carb bowl is rotated in a way that doesn't allow the float to drop down far enough to open the needle valve.

3. It is possible that the factory incorrectly set up the carb, and it has never been quite right. This, however, is more apt to be the case with more expensive mowers. 


It won't hurt anything to put a new gas-line filter in, though that's probably not the issue. Make sure that, if you do install a new gas filter, you have the direction correct.


The bottom line is that this is almost certainly a minor problem with your carb. If you're at all savvy with small engines, you'll be fine.


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## biggles (Jan 1, 2008)

drop the gas float assembly that nut has an opening in it that the fuel goes up into the engine piece of grass or dirst is starving the inlet..you'll see it...


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