Joyner JNSZ1600QL Owner's Manual page 106

12. Engine power is not enough.
Cause
(1). Incorrect Ignition timing
(2). Incorrect Timing belt assembly or
(3). Carburetor float chamber level too low or
needle fuel intake strainer blocked valve and strainer
(4). Throttle valve not widely open
(5). Choke not widely open or auto-choke damaged
(6). Fuel filter blocked
(7). Abnormal or too low cylinder compression pressure
(8). Spark plug corroded, damaged or Spark plug gap abnormal
(9). Intake manifold or connecting hose vacuum leaking
13. Carburetor backfire.
Cause
(1). Engine ignited too late
(2). Incorrect Timing belt assembling or
(3). Carburetor fuel level too low or
(4). Carburetor measuring orifice blocked or
(5). Spark plug overheated or too much carbon deposits
(6). Intake valve sealing not well
(7). Intake manifold or connecting hose vacuum leakage
14. Oil pressure warning light is illuminated during engine running.
Cause
(1). Engine oil level too low or not correct
(2). Oil pressure warning light woks abnormally
(3). Engine temperature too high
(4). Engine bearing or fuel pump worn out
(5). Fuel pump relief valve binding or spring deformed
Adjust 'teeth'belt tension or tension incorrect belt tension pulley.
Adjust 'teeth'belt tension and tension pulley inadequate
belt tension
Check and adjust float chamber needle valve mixture
too lean
Fill in engine oil or apply correct engine oil
105
Correction
Check or adjust distributor
Check and clean carburetor float
Adjust
Adjust or service
Replace
Check and service
Replace spark plug
Check or service
Correction
Check or adjust distributor
Clean float chamber watery
Adjust and service
Check and service
Check and service
Correction
Replace Oil pressure warning light
See No. 17.
Check, service or replace
Check or replace