Troubleshooting Guide
ENGINE DOES NOT START
What To Check
Does the engine crank?
YES
Good compression?
YES
Does the tank contain fresh fuel of the proper grade?
YES
Is fuel visible and moving in the return line when priming?
YES
Is there spark at the spark plug wire terminal?
YES
Check the spark plug.
Possible Cause
Faulty recoil starter.
NO
Fluid in the crankcase.
Internal damage.
Loose spark plug.
NO
Excess wear on cylinder, piston, rings.
Fuel incorrect, stale or contaminated; NO
mixture incorrect.
NO Check for clogged fuel filter and/or vent. Priming pump not functioning properly.
The ignition switch is in “O” (OFF) NO
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.
The plug is damaged internally or of the wrong size.
Remedy
Consult with an authorized servicing dealer.
Tighten and
Consult with an authorized servicing dealer.
Refill with fresh, clean unleaded gasoline with a pump octane of 87 or higher mixed with
a
Replace fuel filter or vent as required; restart.
Consult with an authorized servicing dealer.
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 0.024 - 0.028 inch (0.6 - 0.7 mm). Restart.
Replace the plug with an NGK BPMR6A or equivalent resistor type spark plug of the correct heat range. Set spark plug electrode gap to 0.024 - 0.028 inch (0.6 - 0.7 mm).
LOW POWER OUTPUT
| What To Check |
| Possible Cause |
| Remedy | |
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| Operator is overworking the unit. |
| Shorten trimmer line. Cut at a slower rate. | |
| Is the engine overheating? |
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| Carburetor mixture is too lean. |
| Consult with an authorized servicing dealer. | |
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| Improper fuel ratio. |
| Refill with fresh, clean unleaded gasoline with | |
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| a pump octane of 87 or higher mixed with | |
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| a | |
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| exceeds | |
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| oils at 50:1 gasoline/oil ratio. | |
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| Fan, fan cover, cylinder fins dirty or |
| Clean, repair or replace as necessary. | |
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| damaged. |
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| Carbon deposits on the piston or in |
| Consult with an authorized servicing dealer. | |
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| the muffler. |
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| Clogged air cleaner element. |
| Service the air cleaner element. | |
| Engine is rough at all |
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| speeds. May also have |
| Loose or damaged spark plug. |
| Tighten or replace. | |
| black smoke and/or |
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| unburned fuel at the |
| Air leakage or clogged fuel line. |
| Repair or replace filter and/or fuel line. | |
| exhaust. |
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| Water in the fuel. |
| Replace the fuel. See page 10. | |
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| Piston seizure |
| Consult with an authorized servicing dealer. | |
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| Faulty carburetor and/or diaphragm. |
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| Oveheating condition. |
| See above(Engine overheating). | |
| Engine is knocking. |
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| Improper fuel. |
| Check fuel octane rating; check for presence of | |
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| alcohol in the fuel (page 10). Refuel as necessary. | |
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| Carbon deposits in the combustion |
| Consult with an authorized servicing dealer. | |
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| chamber. |
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