User Guide

9-2
STARTING FAILURE/HARD STARTING/POOR ENGINE IDLE SPEED
PERFORMANCE/POOR MEDIUM-AND HIGH-SPEED PERFORMANCE
TRBL
SHTG
COMPRESSION SYSTEM
Cylinder and cylinder head
 Loose spark plug
 Loose cylinder head or cylinder
 Faulty cylinder head gasket
 Worn, damaged or seized cylinder
 Improperly sealed valve
 Improper valve-to-valve seat contact
 Improper valve timing
 Faulty valve spring
Piston and piston ring
 Improperly installed piston ring
 Worn, fatigued or broken piston ring
 Seized piston ring
 Seized or damaged piston
Crankcase and crankshaft
 Improperly seated crankcase
 Seized crankshaft
EB901000
POOR ENGINE IDLE SPEED PERFORMANCE
POOR ENGINE IDLE SPEED PERFORMANCE
Carburetor
 Improperly returned starter plunger
 Loose pilot jet
 Clogged pilot air jet
 Improperly synchronized carburetors
 Improperly adjusted idle speed
(throttle stop screw)
 Improper throttle cable free play
 Flooded carburetor
Electrical system
 Faulty battery
 Faulty spark plug
 Faulty ignitor unit
 Faulty pickup coil
 Faulty ignition coil
Valve train
 Improperly adjusted valve clearance
Air filter
 Clogged air filter element
EB902000
POOR MEDIUM-AND HIGH-SPEED PERFORMANCE
POOR MEDIUM-AND HIGH-SPEED PERFORMANCE
Refer to “STARTING FAILURE/HARD STARTING”. (Fuel system, electrical system, compression
system and valve train)
Carburetor
 Faulty diaphragm
 Improperly adjusted fuel level
 Clogged or loose main jet
Air filter
 Clogged air filter element
Fuel pump
 Faulty fuel pump