Lawn Mower jerks instead of starting.?

Question

Im afraid my son broke my lawn mower. He ran over a tree stump now instead of it starting up..it just jerks and smokes. Ive looked at the air filter..ok..and just added new gas..Is there anything else I can do? I really dont have the money to take it in to a professional.

Answer 1

For the the engine to blow smoke it either has the wrong fuel or you have turned the mower over to inspect the blades and allowed oil to get into the cylinder.They way you described it it sounds like it is fould with oil and it wont run properly till the oil has cleaned out.

Remove the plug, with the control in the off position pull the cord a few times to make sure the cylinder is clean. Clean the plug check the gap.Refit the plug and start it. It may require this procedure a couple of times.

Answer 2

Sounds as though hitting the stump jammed the cutting blade and either broke or twisted the shaft that turns it. Worst case is the shaft may have broken at the top end within the engine casing itself.

In the absence of professional help can't you seek out a handy neighbour that will look at it for you?

It really needs to go up on a bench and be at least partially dismantled.

Sorry.

Answer 3

Follow the instructions of 2n2222 paying particular attention to something obstructing the blade or a bent crank shaft.  Oil may also have splashed up into the cylinder and fowled the spark plug.  It will need to be cleaned.  It sounds like it wants to start.  I think your problem  may be a bent or split shear pin.  This will cause the engine to run out of time.  It is firing but the piston is not in the proper position.  The shear pin is designed for situations such as this.  To fix it, you will have to remove the flywheel.  Getting it off may be a bit difficult because the pin is bent in the flywheel's slot.  You may have to gently hammer the flywheel in the opposite direction of rotation to break it loose.  When you get the key out (It would look like a small metal chip or block), replace it with a new one.  You can get one from any small engine repair shop.  You shouldn't have to take it in to a repair shop to do this.

Answer 4

First, pour the gasoline back into the container.  Then find an appropriate wrench and remove the spark plug.  This last step is partially for safety and partially so you can see if the engine is rotating freely.  

Then flip the mower onto its side, preferably with the exhaust pipe down so that the oil doesn't drain into the carburetor and make it hard to start later,  and have a look.  

To see if the engine rotates freely, you'll probably have to pull up on the engine-kill handle--that is, the handle that you have to pull up on when you're mowing or it stops the engine.  Then rotate the blade and see what happens.  If you've bent the crankshaft you're probably out of luck, but if only the blade is bent and is hanging up on something, either un-bend or replace the blade; it's not too hard to do.  

Good luck with it.  There are several lawn-mower-repair sites, and the tools are inexpensive.