找到一片文章，准备一步步试试
My mower won't start
Starting problems with your lawn mower fall into 2 basic causes: fuel
problems and ignition problems. The following is a simple checklist you can
follow to help isolate a possible cause. This is not an exhaustive guide and
certainly not a repair manual. However, there a few steps you can take
before taking it to the repair shop for a thorough fix.
Fuel
This is the first and most obvious thing to check, especially if you weren't
having startup problems last year. Be sure that the machine has an ample
supply of fresh fuel. It's amazing how often people will get their mower out
of cold storage the first warm day in spring and find their mower just won'
t start. Forgetting that they left the fuel in the tank from the previous
year. Today's fuels don't age well. In fact today's gasoline is much like
milk and starts to go bad quickly, often in as short a period as 60 days.
Ignition
Make sure that the ignition switch is "on", that all attachments are
disengaged and that the transmission is in neutral. Most machines have
safety mechanisms that will not allow them to start otherwise. Consult your
owner's manual for the starting procedure for your machine.
Make sure the spark plug wire is firmly attached to the spark plug.
If it still doesn't start, check for a spark by removing the spark plug and
grounding the "hex" part of the spark plug to a bare metal part of the
engine. Remove any spilled gasoline that is nearby first, then spin the
engine by pulling the rope or turning the key. You should see a blue spark
jump across the plug gap. If you have a good hot spark, skip to the
carburetor section.
lf the spark is yellow and weak, or there is no spark then the first thing
to do is try a new spark plug. Don't try cleaning the old one. Set the new
plug gap to the proper spec (usually 0.030") and check for spark again. If
you do see a spark, install the new plug and try to start the machine.
If there's still no spark, try cleaning and setting the points on older
machines, or replacing the electronic ignition module on newer machines.
Before replacing the old module test it by disconnecting all the wires from
the module terminal that connect to the kill switches and recheck for spark
, if you do see a spark then a wire or switch is probably defective. Also
check the flywheel key. That affects the spark timing, usually the key will
need replacing if you strike something while mowing and the engine stops.
Checking the carburetor and fuel system
If the fuel is fresh, you have a good spark and still won't start, you must
make sure that fresh gasoline is getting to the carburetor. Make sure that
the fuel shutoff valve (if present) is opened, and that the fuel line is
not plugged or kinked.
Also be sure the fuel cap vent is open and any screens in the tank are clear
of debris. If fuel can flow to the carburetor, carefully place 1 teaspoon
of gasoline down the spark plug hole (or a add shot of starting fluid into
the carburetor throat). Re-tighten the plug and try to start the machine. If
it runs for a second or two, then quits, chances are the carburetor needs
to be serviced (disassembled and cleaned & inspected, then rebuilt) or you
have an air leak somewhere.
Make sure all mounting screws or bolts are snug and gaskets are not missing
sections. If the carburetor is a bowl-type check for water in the bottom of
the bowl (but do not let the float swing all the way down or the float
needle will fall out!).
