Shindaiwa 502s User Manual

18

Does the engine crank?

Good compression?

Does the tank contain 

fresh fuel of the proper 

grade?

Is fuel visible and mov-

ing in the return line 

when priming?

Is there spark at 

the spark plug wire 

terminal?

Check the spark plug.

The plug is damaged internally or  of the 

wrong size.

Faulty recoil starter.
Fluid in the crankcase.
Internal damage.

Loose spark plug.
Excess wear on cylinder, piston, rings.

Fuel incorrect, stale, or contaminated;  

mixture incorrect.

Check for clogged fuel filter and/or vent.

The ignition switch is in “O” (OFF) 

position.

Shorted ignition ground.
Faulty ignition unit.

If the plug is wet, excess fuel may  be in 

the cylinder.

The plug is fouled or improperly gapped.

Consult with an authorized servicing dealer.

Tighten and re-test.
Consult with an authorized servicing dealer.

Refill with fresh, clean unleaded gasoline 

with a pump octane of 87 or higher mixed 

with 50:1 Shindaiwa Premium 2-cycle 

mixing oil or with an equivalent high 

quality 2-cycle mixing oil.

Replace fuel filter or vent as required. 

Restart.
Move switch to “I” (ON) position and restart.

Consult with an authorized servicing dealer.

Crank the engine with the plug 

removed, reinstall the plug, and restart.
Clean and regap the plug to 0.6mm-

0.7mm. Restart.
Replace the plug. Check the Specifications 

page for the correct spark plug. Restart.

Is the engine overheating?

Engine is rough at all speeds. 

May also have black smoke 

and/or unburned fuel at the 

exhaust.

Engine is knocking.

Operator is overworking the unit.
Carburetor mixture is too lean.
Improper fuel ratio.

Fan, fan cover, cylinder fins dirty or 

damaged.
Carbon deposits on the piston or in the 

muffler.

Overheating condition
Improper fuel

Carbon deposits in the combustion chamber.

Clogged air cleaner element.
Loose or damaged spark plug.

Air leakage or clogged fuel line.
Water in the fuel.

Piston seizure.
Faulty carburetor and/or diaphragm.

Consult with an authorized servicing dealer.

Cut at a slower rate.
Consult with an authorized servicing dealer.
Refill with fresh, clean unleaded gasoline 

with a pump octane of 87 or higher mixed 

with 50:1 Shindaiwa Premium 2-cycle 

mixing oil or with an equivalent high 

quality 2-cycle mixing oil.
Clean, repair or replace as necessary.

Consult with an authorized servicing dealer.

Clean or replace the air filter.
Tighten or replace the plug. Check the 

Specifications page for the correct spark 

plug. Restart.
Repair or replace fuel filter and/or fuel line.
Refill with fresh fuel/oil mixture.

Consult with an authorized servicing dealer.

See above.
Check fuel octane rating; check for 

presence of alcohol in the fuel. Refuel as 

necessary.