MT-74FA —TROUBLESHOOTING GUIDE
TABLE 4. ENGINE TROUBLESHOOTING
SYMPTOM | POSSIBLE PROBLEM | SOLUTION | |
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Difficult to start |
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| Ignition plug being bridge? | Check ignition system. | |
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Fuel is available but spark plug | Carbon deposit at ignition? | Clean or replace ignition. | |
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will not ignite. (Power available | Short circuit due to defective | Replace insulators. | |
at high tension cable). | |||
insulators? |
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| Improper spark gap? | Set spark plug gap to the correct gap. | |
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Fuel is available but spark plug | Short circuit at stop switch? | Check stop switch circuit. Replace stop switch if defective. | |
will not ignite. (Power NOT |
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available at high tension cable). | Ignition coil defective? | Replace ignition coil. | |
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| Muffler clogged with carbon | Clean or replace muffler. | |
| deposits? |
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Fuel is available and spark plug |
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Fuel in use inadequate (water, | Flush fuel sytem and replace with fresh fuel. | ||
ignites (compression normal). | |||
dust)? |
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| Air Cleaner clogged? | Clean or replace air cleaner. | |
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| Defective cylinder head gasket? | Tighten cylinder head bolts or replace head gasket. | |
Fuel is available and spark plug |
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Cylinder worn? | Replace cylinder. | ||
ignites (compression low ). | |||
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| Spark plug loose? | Tighen spark plug. | |
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Operation not satisfactory |
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| Air cleaner clogged? | Clean or replace air cleaner. | |
Not enough power available |
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(compression normal, no | Air in fuel line? | Bleed (remove air) from fuel line. | |
misfiring). |
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Carbon deposits in cylinder? | Clean or replace cylinder. | ||
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| Ignition coil defective? | Flush fuel sytem and replace with fresh fuel. | |
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Not enough power available | Ignition plug often shorts? | Replace ignition wires, clean ignition. | |
(compression normal, misfiring). |
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Fuel in use inadequate (water, | Flush fuel sytem and replace with fresh fuel. | ||
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| dust)? |
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| Mined fuel quality is inadequate? | Check fuel to oil mixture. | |
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| Excessive carbon deposits in | Clean or replace crankcase. | |
Engine overheats. | combustion chamber? |
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Exhaust or muffler clogged with | Clean or replace muffler. | ||
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| carbon? |
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| Spark plug heat value incorrect? | Replace spark plug with correct type spark plug. | |
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