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1-8-4 Troubleshooting for slow run (troubled engine)
Poor slow run
Analysis of potential causes
Check for contamination in spark plugs and excessive gap
Fair
Poor
Alarming abnormality of ignition timing
Cleaning and
adjustment
Poor
z
Dirty spark plugs
z
Incorrect spark plug
gaps
z
Incorrect ignition
timing
z
Obstructed air filter
grill
z
Poor carburetor
buoyant needle valve
z
Poor carburetor choke
valve
z
Poor engagement of
carburetor and inlet
tube
z
Obstructed carburetor
slow injection
z
Poor engagement of
cylinder head washer
z
Severe wear of
cylinder, piston, piston
ring
Replacement of
the filter grill
Is the carburetor buoyant
level normal ?
Fair
adjustment
Is the air filter grill
obstructed?
Poor
Fair
Adjustment or
replacement of the
buoyant needle valve
Fair
Poor
Check if the choke
valve fails (valve
does not open) ?
Check of for air between the
carburetor and the air inlet
Fair
Poor
Correction
Check for obstruction in the
carburetor slow injection
Fair
Poor
Add tightening force or
replacement of the washer
Fair
Poor
Cleaning
Test the compression
Check for air leakage in the cylinder washer,
check wear of cylinder, piston, piston ring
and other elements with correction,
adjustment or replacement