ENGINE CRANKS
NORMALLY, BUT
WILL NOT START
(Cant.)
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following items
The choke plate and linkage for binding.
The fast idle cam for binding.
Thermostatic spring housing adjustment.
Fuel supply at the carburetor
Work the throttle by hand several times. Each time the throttle is actuated, fuel should spurt from the accelerating pump discharge nozzles.
If fuel is discharged by the accele-rating pump, the engine is probably flooded, or there is water in the fuel system or an engine mechanical item is at fault.
If fuel is not discharged by the accelerating pump, disconnect the carburetor fuel Inlet line at the carburetor. Use a suitable container to catch the fuel. SwItch on the
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ignition and see if fuel is reaching the carburettor.
If fuel is not reaching the carburettor, check
The fuel filter.
The fuel pump.
The carburettor fuel inlet line for obstructions.
The pump fuel flexible Inlet line for a collapsed condition.
The fuel tank line for obstructions.
The fuel tank vent.
If fuel is reaching the carburettor, check
The fuel inlet system including the fuel inlet needle and seat assembly and the float assembly.
Engine
Mechanical failure in camshaft drive.
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ENGINE STARTS, BUT
FAILS TO KEEP
RUNNING
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FUEL SYSTEM
Idle fuel mixture needle(s) not ~properly adjusted.
Engine Idle speed set too low.
The choke not operating properly.
Float setting incorrect.
Fuel inlet system not operating properly.
Dirt or water in the fuel lines or in the fuel filter.
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Carburettor icing.
Fuel pump defectIve.
Check for dirt in the carburettor not allowing fuel to enter or be dis-charged from the idle system.
IGNITION SYSTEM
Leakage in the high tension wiring.
Open circuit in primary resistance wire. |
ENGINE RUNS,
BUT MISSES
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Determine if the miss is steady or erratic and at what speed the miss occurs by operating the engine at various speeds under load.
MISSES STEADILY AT ALL
SPEEDS
Isolate the miss by operating the engine with one cylinder not firing. This is done by operating the en-gine with the Ignition wire removed from one spark plug at a time, until all cylinders have been checked. Ground the spark plug wire removed.
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If the engine speed changes when a particular cylinder is shorted out, that cylinder was delivering power before being shorted out. If no change in the engine operation is evident, the miss was caused by that cylinder not delivering power before being shorted out. In this case, check the:
Ignition system
If the miss is isolated in a particular cylinder, perform a continuity test on the ignition lead of that cylinder.
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