Dead lawn mower?
staring at a
yard full of
two weeks ago,
the last thing
you want is a
won’t fire up.
have a heart
on the rip cord
of your lawn
check the fuel
They’re the root
causes of more
than 80 percent
I’ll walk you
hand tools and
a socket set, a
can of carburetor
your air compressor.
have to make a
trip to the
parts store. But
after an hour of
effort, you just
might have an
you’ll save a
bundle by fixing
it yourself. Let’s
Check the plug
I’ll assume you’ve cleaned the air filter,
so the next step is to remove the spark
plug to see if it’s wet. If it is, there’s no
way the engine will start. So clean the
plug with carburetor cleaner and let it
dry. Cleaning it with compressed air isn’t
enough; you need a solvent to remove oil
residue. If the plug was wet, move on to
Step 3. If it was dry, skip to Step 4.
If the fuel is more than a month old,
dispose of it properly and refill the tank
with fresh gas. Then reinstall the spark
plug and try starting. It may take quite a
few pulls to suck the new gas into the
carburetor, so be prepared to clean and
dry the plug a few more times.
Check the carburetor bowl for gas
1 of 4
Photo 1: Remove the bowl
Set a small cup under the
carburetor to catch any spills. Then
loosen the bowl nut with a socket.
Once the nut is loose, unscrew it by
hand and lower the bowl. Gas should
2 of 4
Photo 2: Remove the inlet needle and seat
Pull the float pin straight out. Catch
the float, inlet needle and retaining
spring with a rag. Remove the rubber
seat with a small pick. Reverse the
procedure to install the new parts.
3 of 4
Photo 3: Check carb condition
Examine the inside of the
carburetor. If you see chalky/powdery white corrosion like this,
the carb is a goner.
4 of 4
Photo 4: Fellow DIYer's solution for corroded carburetor
An anonymous reader from Oakland, ME took issue with my statement that finding corrosion in a small engine carburetor means "game over." Instead he advises boiling the disassembled carburetor in vinegar for 30 minutes. He says the pitting will remain, but the vinegar will remove the rest of the corrosion. Since vinegar is cheap, you've got nothing to lose but time.
The engine can’t get gas if the fuel filter
is plugged or the carburetor inlet needle
is stuck. Check the fuel filter (if
equipped) by removing the fuel line at
the carburetor. Gas should run out. If it
doesn’t, remove the fuel line ahead of
the fuel filter inlet. If gas flows, the filter
is clogged. Replace it. If you still don’t
get any gas, the fuel line is kinked or
plugged. And check inside the tank for
any debris that might clog the outlet.
If you’re getting gas to the carburetor,
check to see if there’s any fuel in the bowl.
Clamp off the fuel line with a C-clamp.
Then remove the bowl (Photo 1). If the bowl
is empty, the problem is a stuck inlet
needle and seat. They’re easy and cheap to
replace (Photo 2). But before you buy the
parts, check the condition of the rest of the
carburetor’s interior (Photo 3). If you see
any corrosion, it’s “game over.” A corroded carburetor is a dead carburetor. Replace it.
Clean the jet
1 of 1
Photo 5: Clean the main jet
Remove the carburetor bowl nut.
Insert the carburetor cleaner straw
directly into the main jet passage and
squeeze the trigger on the can several
times until the spray shoots into the
venturi of the carburetor. That'll confirm
the passage is open.
A clogged main jet is a pretty
common problem. You can try
cleaning it with spray carburetor
cleaner (Photo 4). Then try starting.
If the engine still isn't getting
gas, replace the carburetor.
If it starts but runs rough
If you got the engine to start by cleaning
the main jet, but it runs rough or the idle
speed surges, you have two choices—rebuild or replace the carburetor. For
rebuilding instructions, see “How to repair small engines.”
Otherwise, disconnect the old carburetor
from the linkage, remove the two retaining bolts and slap on a new carburetor.