Cobra Y173V - Power Lack

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4. DISASSEMBLING AND SERVICING
CYLINDER PRESSURE
METER
 Turn the fuel cock to “OFF” position, and drain the gasoline of the carburetor.
 Remove the spark plug and spark plug cap
 Pull the recoil starter grip to drain the gas in the cylinder.
 Install the spark plug cap.
 Put the control lever to “low” position.
 Pass negative pole (thread) of the spark plug through cylinder cover to connect
grounding and pull the recoil starter grip to observe the spark.
4-1-2 Power Lack
TROUBLE
CAUSE
REMEDY
When increasing the throttle, speed increase slow or even
decrease and stop running
Ignition System Fuel Supply System
Air in fuel line or fuel line clogged.
Exhaust air or dredge fuel line
Main oil flow hole is not adjusted properly.
Readjust
In carburetor, needle valve hole and main oil
flow hole clogged.
Clean and blow to get through
Fuel cock is clogged up.
Clean, replace damaged part
Too much carbon deposit in combusting
chamber.
Clear away
Too much car bon fouling in muffler and
exhaust pipe.
Clear away
Air cleaner is clogged up.
Clean air cleaner filter element
Intake pipe is leaking.
Repair or replace
Poor Compression
Piston or cylinder or piston ring is worn
Replace the worn
Air leakage from the surface by which cylinder
block contacting with cylinder head.
Replace cylinder gasket
Too big or too small valve clearance.
Readjust
Valve tightness is poor.
Repair
 Drain the oil of the fuel tank out.
 Drain the gasoline by loosening the oil drain bolt of the
carburetor.
 Remove the spark plug cap and spark plug and install the
cylinder pressure meter.
 Forcibly pull the recoil starter several times and measure
compression force. (Compression Force：1.40Mpa/1300rpm)