MVC-70H/HW — TROUBLESHOOTING (ENGINE)
Practically all breakdowns can be prevented by proper handling and maintenance inspections, but in the event of a breakdown, please take a remedial action following the diagnosis based on the Troubleshooting Charts (Tables 8 and 9). If the problem cannot be remedied, please leave the unit just as it is and consult our company's business office or service plant.
TABLE 8. ENGINE TROUBLESHOOTING
SYMPTOM | POSSIBLE CAUSE | SOLUTION | |
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| Spark plug bridging? | Check gap, insulation or replace | |
| spark plug. | ||
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Difficult to start, "fuel is available, but no | Carbon deposit on spark plug? | Clean or replace spark plug. | |
SPARK at spark plug". | Short circuit due to deficient spark plug | Check spark plug insulation, | |
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| insulation? | replace if worn. | |
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| Improper spark plug gap? | Set to proper gap. | |
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| ON/OFF switch is shorted? | Check switch wiring, replace | |
| switch. | ||
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| Ignition coil defective? | Replace ignition coil. | |
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Difficult to start, "fuel is available, and | Improper spark gap, points dirtry? | Set correct spark gap and clean | |
points. | |||
SPARK is present at the spark plug". |
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| Condenser insulation worn or short | Replace condenser. | |
| circuiting? | ||
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| Spark plug wire broken or short circuiting? | Replace defective spark plug | |
| wiring. | ||
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| Wrong fuel type? | Flush fuel system, and replace | |
| with correct type of fuel. | ||
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Difficult to start, "fuel is available, spark |
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Water or dust in fuel system? | Flush fuel system. | ||
is present and compression is normal" | |||
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| Air cleaner dirty? | Clean or replace air cleaner. | |
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| Suction/exhaust valve stuck or protruded? | ||
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| Piston ring and/or cylinder worn? | Replace piston rings and or | |
| piston. | ||
Difficult to start, "fuel is available, spark |
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is present and compression is low" | Cylinder head and/or spark plug not | Torque cylinder head bolts and | |
| tightened properly? | spark plug. | |
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| Head gasket and/or spark plug gasket | Replace head and spark plug | |
| damaged? | gaskets. | |
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| Fuel not available in fuel tank? | Fill with correct type of fuel. | |
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| Fuel cock does not open properly? | Apply lubricant to loosen fuel | |
| cock lever, replace if necessary. | ||
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No fuel present at carburetor. |
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Fuel filter clogged? | Replace fuel filter. | ||
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| Fuel tank cap breather hole clogged? | Clean or replace fuel tank cap. | |
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| Air in fuel line? | Bleed fuel line. | |
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