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lawnmower wont start Answered

I have a pull-lite 3.5 horsepower engine on my used sears mower, I replaced the sparkplug and still no start, I get a flooded carb, could it be the magneto?



7 years ago

Ring or email the mover wreckers for support and cheap parts. They do postal orders too.


8 years ago

sorry to correct Jimc4567  but you need air/fuel mixture, compression and spark.

Charlie  why do you think you have a flooded carb.  after trying to start it do you remove the plug and notice it's wet? or do you see wetness coming out the muffler? or do you have gas dripping from around the carb?

You need to make sure you have spark.  The correct and safe way is by using a spark tester.  It may look like a spark plug with a clip on it,  or it may be an inline tester.  It may spark over a gap or may light a light.   If you don't have one or feel like buying one.  take out the spark plug, leave put the sparkplug back into the sparkplug boot and leave it laying against a bare metal part on the mover.  I don't suggest holding it because the spark will be around 17kV (17,000 volts).  Do it somewhere that isn't in direct light or sunlight so you can see it.   Hopefully you can confirm if you have spark then. If you don't It may be the Ignition coil, or points and condenser depending on what system your mower has.

Compression is a bit hard to gauge because  the motor most likely has a decompressor while at low RPM which drops the compression but makes it considerable easier to pull over.   But if you put the mower away last year or the mower was just running last week I don't it has lost compression unless you have run the unit low on oil and scored it up.

For the air fuel mixture thing,  Make sure your air filter isn't clogged,  you should be able to see light through it.  If it's very clogged, you will make the mower run rich , which may possibly flood the engine.   If there is lots of gas dripping out.  I would suspect a stuck float, or debris on the needle which is holding it open and allowing gas leak into the engine.  

I could go on and on about possible problems, but more info on your end will help you get the right answer

How did the mower last run?  when was it last run?
Is there gas in it?  how old is the gas (how long ago did you buy it)?
oil in the engine?
does it have spark?
why do you think the carb is flooded?
tell us anything else you think might help

If you have any other questions or answers for the above questions,  feel free to message me.


8 years ago

Give it a full service. Change the oil. Change the condenser. Change the plug. Change/clean the air filter. Dismantle and clean the carb. Empty the fuel tank , flush it with clean fuel and refill. Check fuel line for splits and replace.

Or eliminate one thing at a time until it starts.
If you do everything and it still won't go, you're in trouble.


8 years ago

I'm not sure how you determined you have a flooded carb. Probably from the smell of gasoline?

Gas engines need three things to start: air, gas, spark. The easiest thing to check is whether you are getting spark. Remove the spark plug and connect the spark plug cable to it. Use a wire to wrap around the threads of the plug, and connect it to the frame of the mower (anywhere generally). When you pull the cord you should see a spark jump in the gap of the spark plug. You'll only need to pull it once or twice. If you have no spark there is a condenser or capacitor that can go bad, and is a fairly easy component to replace.

These smal engines have a small carburetor that will sometimes stick in several different positions. As Re-design stated the choke or float could be stuck open. Beyond this, you may have to take to a shop to take it apart.


8 years ago

Probably not.  Unless you pulled on it 25-30 times with it not starting.  If it floods then your choke might be stuck.  Or the float may be stuck.  Or the air cleaner might be clogged.

Probably it had old gas left in it last season and that gas had ethanol in it and ethanol absorbes water which then corrodes parts in the carb.  You might try getting all of the gas out and replacing it with new gas and see if that gets you going.  Sometimes it works.  If it does use gas treatment that you can get from the lawnmower shop to stop this from happening next time.