Lawn-Boy M Series User Manual

ENGINE TROUBLESHOOTING CHART (CON'T)
Cause Remedy and Reference
ENGINE LACKS POWER (con’t)
Improper amount
of oil in fuel mixture
Blocked exhaust port
Faulty ignition
Crankcase seals leaking
Worn piston or rings (low compression)
Drain tank;
fill with correct fuel/oil mixture. Adjust oil
injector pump linkage.
(Oil Injection Models).
Clean port.
See electrical system ignition troubleshooting.
Replace
worn crankcase seals.
Overhaul engine.
ENGINE SURGES OR RUNS UNEVENLY
Carburetor throttle linkage or throttle shaft and/or butterfly
Clean, lubricate,
or adjust linkage and deburr throttle shaft
binding or sticking or butterfly.
Fuel
tank cap vent hole dogged open vent hole or replace cap.
Governor sticking or binding
Clean
or repair governor parts as necessary.
ENGINE VIBRATES EXCESSIVELY
Damaged blade
Install piston correctly.
Piston installed incorrectly. Engine wrist pin offset
Replace crankshaft
and connecting rod assembly.
Bent
crankshaft
Replace blade drive collar.
Damaged blade drive
collar
Balance or replace blade.
EXCESSIVE ENGINE RPM
Improper governor spring adjustment Adjust governor spring.
Improper governor lever adjustment
Adjust governor lever. Clean or repair governor parts as
necessary.
Improper fuel/oil mixture
Improper
fuel
Choke partially closed
check valve leaking (start-up only)
Excessive idle (BBC Model)
Drain tank; fill with correct fuel/oil mixture. Adjust oil
injector pump linkage.
(Oil Injection Models).
Use of premixed fuel/oil mixture in oil injected model.
Open
choke. Adjust throttle cable and/or choke linkage.
Test check
valve. Replace if leaking.
Clean muffler of oil deposits.
13-3

Lawn-Boy M Series Specifications

General

Brand	Lawn-Boy
Model	M Series
Category	Lawn Mower
Language	English