Toro Lawn-boy - Engine Pre-Ignites

9
TROUBLESHOOTING
Engine Overheats
Engine Vibrates Excessively
Engine Crankshaft Will Not Turn
Engine Produces Mechanical Knocking Sound
Possible Causes Remedies
Cylinder head coolin
g
fins clo
gg
ed Clean fins thorou
g
hly
Restricted carburetor jets Clean carburetor and jet
Improper
g
as to oil mix ratio Ensure mixture is correct
Coolin
g
air intake plu
gg
ed Remove forei
g
n material and clean
Possible Causes Remedies
Blade out of balance Balance blade or replace if dama
g
ed
Bent blade Replace blade
Loose en
g
ine mountin
g
screws Ti
g
hten en
g
ine mountin
g
screws (en
g
ine to plate, plate
to mower housin
g
)
Bent crankshaft Replace crankshaft
Flywheel out of balance (dama
g
ed) Replace flywheel
Possible Causes Remedies
En
g
ine brake incorrectly en
g
a
g
ed Disen
g
a
g
e brake and inspect and repair as necessary,
mower only
Blade jammed in housin
g
Inspect and repair or replace, mower only
Piston seized in its cylinder Inspect and repair or replace
Starter jammed Repair starter
Possible Causes Remedies
Loose blade Inspect and ti
g
hten blade nut to correct torque, mower
only
Loose flywheel Inspect and ti
g
hten flywheel nut to correct torque
Pre-i
g
nition is occurrin
g
See “En
g
ine Pre-I
g
nites” table
Loose rod cap Replace rod and bearin
g
s
Loose en
g
ine mountin
g
bolts Ti
g
hten bolts