Section 03 TROUBLESHOOTING
Subsection 01 (TROUBLESHOOTING CHART)
03-01-4 SMR2000-042-03-01.FM
ENGINE MISFIRES, RUNS IRREGULARLY (cont’d)
OTHER OBSERVATION POSSIBLE CAUSE REMEDY
Lean fuel mixture
Dry spark plug (except
when water fouled)
• Low fuel level • Check/refill
• Stale or water fouled fuel • Check/siphon and refill
• Fuel filter dirty or restricted • Check/clean/replace
• Carburetion dirty or out of adjustment
(carburetor models)
• Check/clean/adjust, refer to section
FUEL SYSTEM
• Clogged direct injectors
(DI models)
• Remove and clean direct injectors
• Defective sensor or MPEM
(DI models)
• Check faulty codes in MPEM memory, re-
fer to section ENGINE MANAGEMENT
• Leaking crankshaft seal(s) or intake
(carburetor models)
• Pressure check engine, refer to section
ENGINE
• Restricted fuel valve
(carburetor models)
• Check/replace
• Loose carburetor
(carburetor models)
• Tighten carburetors
Rich fuel mixture
Fouled spark plug
• Partially closed choke
(carburetor models)
• Check/adjust choke cable
• Carburetor adjustment
(carburetor models)
• Check/adjust, refer to section FUEL
SYSTEM
• Loose main jet (carburetor models) • Check, refer to section FUEL SYSTEM
• Improper air/fuel rail pressure
(DI models)
• Check pressures, refer to ENGINE
MANAGEMENT
• Direct injector(s) (DI models) • Remove and replace direct injector(s),
refer to section ENGINE MANAGE-
MENT
• Defective sensor or MPEM
(DI models)
• Check faulty codes in MPEM memory,
refer to section ENGINE MANAGE-
MENT
• Damaged reed valve • Check, refer to Bottom End in ENGINE
SECTION
• Leaking crankshaft seal(s) or intake (DI
models)
• Pressure check engine, refer to section
ENGINE
• Leak in RAVE valve system
(DI models)
• Check, refer to ENGINE MANAGEMENT
• Oil injection pump adjustment • Check/adjust, refer to section LUBRI-
CATION SYSTEM
• Worn needles and seals
(carburetor models)
• Check, refer to section FUEL SYSTEM
• Fuel pressure and/or air pressure fluc-
tuating (DI models)
• Inspect fuel and air pressure regulators.
Refer to ENGINE MANAGEMENT
Start but run poorly
– DI models: check spark plug condition,
check fault codes in the MPEM mem-
ory, check fuel pressure, check RAVE
valves operation.
• Check, refer to section ENGINE MAN-
AGEMENT. If some work has been per-
formed on the unit, make sure injector
wire connectors were not mixed. Refer
to the wiring diagram for wire colors and
positions
Also fuel injection
misinjecting
– DI models: Bent or missing tooth on
encoder wheel.
• Check, refer to ENGINE MANAGE-
MENT under Component inspection
and adjustment
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